A critique of the epidemiological studies on health in allegedly endosulfan-affected areas in Kasaragod, Kerala

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COMMENTARY
CURRENT SCIENCE, VOL. 104, NO. 1, 10 JANUARY 2013
16
A critique of the epidemiological studies on health in allegedly
endosulfan-affected areas in Kasaragod, Kerala
K. M. Sreekumar and K. D. Prathapan
Conference of Parties to the Stockholm
Convention in its fifth meeting held at
Geneva in April 2011 added endosulfan
to the United Nations’ list of persistent
organic pollutants to be eliminated
worldwide1. Endosulfan, a widely used
insecticide, is targeted for elimination
from the global market by 2012. Health
problems in Kasaragod district in Kerala,
where endosulfan was aerially sprayed
for two decades, was the focal point
of an international campaign that
culminated in the global ban of the
insecticide2. Circumstances link the
alleged health problems in Kasaragod
district to the aerial application of endo-
sulfan.
The Government of Kerala instituted
an Expert Commission headed by A.
Achyuthan and the National Human
Rights Commission instituted the Natio-
nal Institute of Occupational Health
(NIOH) to investigate into the issue
separately. The Achyuthan Commission
and the NIOH3 that studied the issue in
2001 and 2002 respectively, recommen-
ded a detailed epidemiological survey in
the area. The survey was conducted only
in 2010. This study was undertaken by
Prabhakumari and co-workers from the
Calicut Medical College (CMC), Kerala.
A report of this study was submitted to
the Prime Minister by the Minister
for Health and Family Welfare, Govern-
ment of Kerala. A partial report of this
study, when published by the Delhi-
based Centre for Science and Environ-
ment (CSE) on their website4 (Note 1),
gained publicity all over the world and
was filed before the Supreme Court of
India. Thanks to the Right to Information
(RTI) Act, we received a copy of the
original research report5, submitted to the
Government of Kerala. Another epide-
miological study was conducted by
Embrandiri et al.6 during 2008–09 in five
affected Panchayaths, involving 1000
respondents.
Our critique of the CMC study is
based on both the study reports. The
methodology and other aspects of the
study are critically analysed here.
Calicut Medical College study
Methodological issues
Research design: The CMC study is a
comparison of the health problems of
1000 families of Bovikkanam Village in
Muliyar Panchayath affected by the
pesticide application, with that of 850
families in Banam Village in Kodom-
Belur Panchayath where no pesticide was
applied. However, the people of Bovik-
kanam and Banam are not comparable as
they are dissimilar socially and economi-
cally. The Muslim population in North
Malabar is socio-economically back-
ward7. The population of muslims in
Banam is only 15% and that of Bovi-
kanam is 45%. This difference is reflec-
ted in the food habits as well as the
health and educational status of the peo-
ple in these areas. Eleven Panchayaths in
Kasaragod district are affected by the
aerial spraying of endosulfan. However,
it is stated in the report that ‘one Pancha-
yath–Muliyar, with large number of
victims was selected randomly’ (p. 6)5
(emphasis added). A well-designed study
based on adequate number of representa-
tive samples would have yielded unequi-
vocal and conclusive results. Evidently,
no attempt was made in this direction.
Operationalization of parameters: The
various parameters of health studied
were not properly defined. For example,
there are many types of liver diseases,
including infective jaundice. It is not
clear which types of liver diseases were
included. Without providing working
definition of a parameter, it cannot be
studied clearly.
Pesticide residue analysis: Endosulfan
residues in the blood plasma of 41 sub-
jects from 11 Panchayaths were analy-
sed. However, no attempt was made to
compare these values with those from the
reference population, which is intriguing.
Thus it is impossible to make compari-
sons and draw valid conclusions with
regard to this important parameter under
study. Gas chromatography (GC) was
used for the analysis of pesticide resi-
dues. However, mass spectroscopy (MS)
was not done to confirm the results. The
Government of India has made it manda-
tory to confirm the analytical values with
MS in the laboratories under the All-
India Network Project on pesticide resi-
dues. The study on endosulfan residues
by CSE8, turned out to be a blunder3, as
they did not confirm the results with MS.
Triangulation: The conclusions of the
CMC study are largely based on subjec-
tive parameters. The information gath-
ered is mainly based on memory recall
by the subjects. No effort was made to
cross-check this information with other
easily available documented facts. For
example, death and birth data are accu-
rately documented in the Panchayath
offices, which is a fairly reliable source
of information to study any possible
change in the demographic pattern. Simi-
larly, local veterinary hospitals record
unnatural death in cattle. Banks and
insurance companies too have a database
of morbidity and mortality in cattle, as
they pay compensation. No attempt was
made to make use of such readily avail-
able information. The study was con-
ducted at the peak of propaganda by the
local clubs and the visual media. Hence
it is highly probable that the responses of
the subjects were biased and hence the
inferences of the study are erroneous and
misleading.
Sociological confounding issues ignored:
The reproductive health events in women
above 30 years (whose reproductive
period was during the period of aerial
spraying) have been compared with those
in women aged below 30 years (whose
reproductive period started after the ces-
sation of the aerial spraying; Table 1).
This study had been designed to assess
plausible improvement in the reproduc-
tive health of women following with-
drawal of endosulfan application. The
study report has specified that data on
the reproductive health events in all mar-
ried women in the study area were col-
lected. However, women are literally

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CURRENT SCIENCE, VOL. 104, NO. 1, 10 JANUARY 2013 17
Table 1. Reproductive health events*
Area I – Muliyar Area II – Banam
N = 2986 N = 1872
Reproductive health events No. % No. % OR 95% CI P value
Treatment for infertility 104 1.7 31 0.8 2.08 1.39–3.31 <0.0001
Abortion 229 7.7 82 4.4 1.81 1.40–2.35 <0.0001
Intrauterine death/stillbirth 64 2.1 18 1.0 2.26 1.33–3.62 <0.0001
Neonatal/infant/child deaths 100 3.3 43 2.3 1.47 1.03–2.12 <0.035
*Reproduced from Prabhakumari et al.5.
Table 2. Physical disability in population below 20 years*
Area I – Muliyar Area II – Banam
Age group No. % No. % OR 95% CI P value
<9 years; N = 961 5 0.5 <9 years; N = 517 7 1.4 0.38 0.12–1.21 0.084
10–19 years; N = 1184 13 1.1 10–19 years; N = 606 1 0.2 6.7 0.57–51.5 0.025
*Reproduced from Prabhakumari et al.5.
transplanted into the family of their
husbands following marriage, under the
Indian family system, for which Kasara-
god is no exception. This means, at least
a section of the women studied by the
CMC researchers was living outside
the study area with their parents during
the period of application of the insecti-
cide. Similarly, many housewives in
Banam (unsprayed reference area) are
likely married into their respective fami-
lies from the neighbouring sprayed areas.
This simple social reality is strong
enough to contort the whole data and
inferences on reproductive health events
in women, as evidently the study is based
on a mixture of subjects from both
exposed and unexposed areas. Generally,
a high proportion of young married men
in muslim families in Muliyar work in
Gulf countries. As a result of the long
spell of separation of couples, chances of
conception are less and it is common that
such couples seek infertility treatment.
This is a strong factor that would distort
the results of the study on the reproduc-
tive health of women as well as their
infertility rates. Moreover, the data on
reproductive health problems during the
period of pesticide application (1980–
2000) was never statistically compared
with the same during the decade after
cessation of the pesticide application.
Inconsistencies in the results and
conclusions of the study
Endosulfan residues in the blood serum
of 41 subjects from the affected areas
were tested and all samples contained
pesticide residues varying from 2.51 to
170.40 ppb (parts per billion), with an
average of 41.65 ppb.
However, the level of endosulfan resi-
dues in blood serum nine months after
the last spray was only 0–12.77 ppb
according to the NIOH study conducted
in 2001. This shows more than fourfold
increase, on an average, in the endosul-
fan residues in the blood serum of
affected people over 10 years! No endo-
sulfan was ever applied in Kasaragod in
the past decade due to the extreme vigil
of the people. According to the study
conducted by the Centre for Water
Resources Development and Manage-
ment (CWDRM), no detectable endosul-
fan residues were observed in water in
the sprayed area. As there is no endosul-
fan in the drinking water, it is surprising
that such extremely high levels of resi-
dues were observed in the blood. Data on
pesticide residues in the blood serum of
41 subjects are provided in the published
report. We statistically compared the
data on pesticide residues in the blood
serum of 41 subjects with the health
status of each individual, provided in the
unpublished report5, and found that
the health status of an individual is not
related to the endosulfan content in
his/her body. Thanks to the RTI Act, we
could obtain copies of the chroma-
tograms of the endosulfan analysis of
blood serum from the Salim Ali Centre
for Ornithology and Natural History.
However, only values of four samples
mentioned in Prabhakumari et al.5 agree
with the chromatogram readings. This
reveals that serious lapses have crept in
the analysis of endosulfan residues.
A parameter that was objectively
assessed is physical disabilities
(Table 2).
The prevalence of physical disabilities
in the age group 1–9 years, in Bovik-
kanam affected by endosulfan spraying is
0.5%, while the same in Banam where no
spraying was undertaken is 1.4%. The
reason for the increased incidence of
physical disabilities in the unsprayed
area is not clarified in the study report.
The study is silent on the incidence of
physical disabilities in the age group 20–
29 born after commencement of the pes-
ticide application. None of the parame-
ters studied was compared with the state
average or national average. Without
comparing the prevalence of every health
parameter in the study area with that of
the state, how is it possible to establish
the epidemiological evidence of the
ill-effects of endosulfan application?
The sex ratio in Bovikkanam is 957
(957 females per 1000 men), while the
same is 1016 at Banam. The researchers
attribute the male-biased sex ratio to the
application of endosulfan, as organochlo-
rine insecticides are implicated in change
of sex ratio. There is no empirical evi-
dence that endosulfan would tilt the sex
ratio towards males. Some studies sug-
gest that organochlorines might reduce
the proportion of male births9–11, while
on the other hand, the opposite also has
been indicated12. However, many studies
in this regard remain inconclusive13.

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CURRENT SCIENCE, VOL. 104, NO. 1, 10 JANUARY 2013
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According to the 2001 census data, out
of the 11 Panchayaths affected by endo-
sulfan application, five have a female-
biased sex ratio. However, boys outnum-
ber girls in the age group 1–6 years in
most of the Panchayaths in the district.
The sex ratio of Muliyar Panchayath that
includes Bovikkanam is 1012. Deriving
conclusions without examining available
facts and figures clearly indicate the bias
of the researchers.
It is stated that the titre of oestrogen in
high-school students was lower while
follicular stimulating hormone and leuti-
nizing hormone were comparatively
higher in Bovikkanam affected by pesti-
cide spraying (Table 3).
This conclusion is wrong as the statis-
tical yardsticks used by the researchers
themselves do not suggest a significant
difference in these measures. Moreover,
the value of standard deviation exceeds
that of mean in the case of oestrogen, in-
dicating high variability and poor quality
of the data.
The study states that reproductive
health events such as abortion, intrauter-
ine death/stillbirth and child deaths were
found to be reduced to 50% among the
age group 20–29 years indicating a
reduction in reproductive health pro-
blems after stopping the pesticide appli-
cation 10 years ago (Table 4).
This inference is not based on any sta-
tistical analysis. A comparison of data on
abortion and neonatal/infant child deaths
of the affected area against that of
Banam (unsprayed area) would prove
this inference to be totally baseless. For
example, the rate of abortion in the
unsprayed Banam in the age group 30–39
years is 4.3% and the same in the age
group 20–29 years is 2.5%. In the affected
Muliyar, rate of abortion in the age group
30–39 years is 7.4% and the same in the
age group 20–29 years is 4.3%. The per-
centage rates of fall in both the sprayed
and unsprayed areas are roughly the
same (42), which may be due to better
access to improved medical facilities.
It is stated5 that the ratio of death
due to any cancer among those below the
age 50 in these areas (sprayed versus
unsprayed) was 11 : 1. However, no
data is provided to substantiate this
statement.
Epidemiological study by
Embrandiri et al.
The epidemiological study by Embran-
diri et al.6 is amateurish and prima facie
unreliable as the methodology followed
is totally flawed. The study was neither
designed properly nor was any statistical
tool adopted for analysis and interpreta-
tion of the data. The prevalence of para-
meters like mental retardation generally
varies from two to five per 1000 indi-
viduals. However, this study is based on
a group of only 1000 individuals, which
is further divided into eight categories
based on age and gender for comparison.
The number of individuals in a category
varies from 77 to 319. With the possibi-
lity of a huge margin of error, this sam-
ple size is too small to derive any
meaningful conclusion out of the study.
The health problems of the affected
population were never compared with
that of an unaffected population, which
is the normal practice in such cases. The
only comparison is between four age
groups, viz. 0–14, 15–30, 31–45 and >46
years. Apparently, the rationale of this
comparison is that the subjects in the age
group 0–14 years were born after cessa-
tion of the pesticide application, most in
the age group 15–30 years were born
during the period of pesticide application
and those above 30 years were born
before the application of the chemical, so
that assessment of the health problems
before, during and after the pesticide
application would give a direct measure
of the impact of the pesticide on the
health of the people in the affected area.
However, this notion is totally flawed, as
many of the health conditions studied
have a strong survival bias or are often
directly age-related. For example, the
median age of survival of an individual
suffering from severe mental retardation
is less than 30 years. Similarly, incidence
of some of the cancers like leukaemia is
more prevalent in children, while some
others like prostrate cancer affect the
elderly. Hence it is totally absurd to
make comparisons between various cate-
gories of age to find out the impact of
endosulfan spraying on the health pro-
blems of a population.
It is stated that ‘random method of sur-
vey was used to select the households’. It
is also stated that ‘data was also col-
lected from the Primary Health Centres
(PHC) and District Medical Officers’.
The methodology followed in the ‘ran-
dom’ selection of the participants is not
clearly stated. However, it appears that
the study is strongly biased as the data
were directly collected from PHCs. This
bias is clearly reflected in the results.
The prevalence of mental retardation re-
ported by Prabhakumari et al.5 is only
two per 1000, whereas the same reported
by Embrandiri et al.6 is 5.2–35.8% in
various age groups of males and females.
According to the 2001 census figures, the
prevalence of mental and physical dis-
abilities in Kasaragod district is only
0.24%. Prevalence of any cancer in the
affected area as reported by Prabhaku-
mari et al.5 is two per 1000. However,
according to Embrandiri et al.6, it varies
from 1.2% to 15.6%. As in the case of
Prabhakumari et al.5, Embrandiri et al.6
too have not bothered to compare the
prevalence of various health problems
with the national average or state average.
The data on the consumption of various
groups of pesticides such as organochlo-
rine and organophosphorus compounds,
provided by Embrandiri et al.6, are out-
dated and erroneous. According to them,
organochlorines are still the most com-
monly used pesticides in India. However,
it remains a fact that after the use of
BHC was banned in India in 1997, the
consumption of organochlorines has re-
duced drastically and the organophos-
phorus pesticides form the largest group
of chemical compounds deployed for
pest control in India14.
Table 3. Sex hormones*
Study group N = 98 Comparison group N = 97
Mean SD Mean SD P value
Oestrogen 51.02 68.24 42.22 51.38 0.32
Follicle stimulating 6.45 5.64 13.01 9.26 0.001
hormone
Leutinizing 5.08 6.84 6.06 9.77 0.433
hormone
Testosterone 1.98 2.94 1.99 2.08 0.989
*Reproduced from Prabhakumari et al.5.

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CURRENT SCIENCE, VOL. 104, NO. 1, 10 JANUARY 2013 19
Table 4. Age of women and reproductive health events*
Area I (Muliyar – sprayed) Area II (Banam – unsprayed)
Age 20–29 years Age 30–39 years Age 20–29 years Age 30–39 years
N = 1220 N = 986 N = 684 N = 623
Reproductive health events No. % No. % No. % No. %
Treatment for infertility 19 1.6 38 3.9 11 1.6 10 1.6
Abortion 53 4.3 73 7.4 17 2.5 27 4.3
Intrauterine death + stillbirth 5 0.4 14 1.4 2 0.3 5 0.8
Neonatal + infant + child deaths 8 0.7 16 1.6 2 0.3 7 1.1
*Reproduced from Prabhakumari et al.5.
Table 5. Prevalence of selected diseases*
Area I – Muliyar (sprayed) Area II – Banam (unsprayed)
N = 6107 N = 3742
Disease Number Prevalence per 1000 Number Prevalence per 1000
Seizure 47 8 39 10
Psychiatric problems 21 4 17 5
Behaviour problems 28 5 4 1
Mental retardation 12 2 7 2
Skin disease 110 18 82 21
Asthma 109 18 113 30
Any cancer 10 2 11 2
Kidney disease 33 5 8 2
History of infertility 44 7 9 2
Liver disease 3 0.5 0 0
Weakness 55 9 27 7
Tremor 9 2 6 2
*Reproduced from Prabhakumari et al.5.
Propaganda and reality
Data on objective parameters generated
by the CMC team, that reflect the reality
of health status of the people in Kasara-
god (Table 5 on p. 13 of Prabhakumari et
al.5), have not been made public. For ex-
ample, 10 out of 6107 individuals
(0.16%) in the pesticide-sprayed area are
cancer patients. However, the number of
cancer patients in the unsprayed refer-
ence population in Banam is 11 out of
3742 (0.29%). The rate of incidence of
mental retardation is equal in both the
populations. The prevalence of skin dis-
eases in the unaffected area is 2.19%,
while that in the pesticide-affected area
is only 1.8%. Asthma, seizure and psy-
chiatric problems too are less in the in-
secticide-sprayed area. Death due to old
age is proportionately higher in the af-
fected Bovikkanam (Table 10; p. 18 of
Prabhakumari et al.5). However, kidney
and liver diseases and the history of in-
fertility are more in the affected area.
The proportion of individuals who
have undergone various surgeries (Table
11 on p. 19 of Prabhakumari et al.5) is
more in the unsprayed Banam (5.85%)
compared to that in Bovikkanam (4.49%;
Table 6).
Surgical rectification of hand or foot
anomaly was less in the endosulfan-
sprayed area. Endosulfan is known as an
endocrine disruptor (the latest toxico-
logical review of the pesticide disputes
this argument15), and is linked to cryp-
torchidism (undescended testis) in boys.
However, according to the unrevealed
data, more surgeries were performed in
the unsprayed area to correct cryptor-
chidism.
Sublethal doses of the pesticide are
likely to affect the foetus during the first
three months of pregnancy. However,
according to Table 7 (table 6 on p. 14 of
Prabhakumari et al.5), the rate of con-
genital organ anomalies and congenital
heart diseases is similar in both places.
Opportunistic use of scientific claims
It is clear that the unsprayed and sprayed
areas do not differ much in terms of the
occurrence of diseases or disabilities.
This vital information has been hidden
from public view. The 2001 census data
show that Kasaragod does not have an
increased rate of any of the mental or
physical disabilities compared to other
districts in the state. There is no reliable
data to prove that there is a higher occur-
rence of any disease or disability in the
sprayed area compared to the unsprayed
area.
The propaganda and fear-mongering is
taking its toll on the lives of the people
in Kasaragod in general and those living
in the affected area in particular. They
are a stigmatized lot due to fears of
genetic defects that would be transmitted
across generations resulting in mentally
and physically challenged offspring. Pro-
spective brides and grooms from the
affected area find it difficult to get suit-
able marriage alliances. There are people
haunted by phobia afflicted by the
propaganda that the soil, water and air
that sustain their life are poisoned. Fol-
lowing reports of allegedly high rates of
cancer, panic-stricken people suspect any
and every illness as cancer and approach
hospitals for treatment. There are also

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CURRENT SCIENCE, VOL. 104, NO. 1, 10 JANUARY 2013
20
Table 6. Reasons for surgery*
Area I – Muliyar Area II – Banam
N = 6107 N = 3742
Reasons for surgery N = 274 Per 1000 population N = 219 Per 1000 population
Uterus-except delivery 41 6.7 45 12.1
Appendicitis 44 7.2 27 7
Hernia 33 5.4 9 2.4
Heart 14 2.3 5 1.3
Genito urinary/kidney 16 2.6 10 2.6
Mouth/throat 15 2.5 19 5.1
Cleft lip 4 0.7 1 0.3
Hand/foot anomaly 4 0.7 3 0.8
Undescended testis 2 0.3 3 0.8
Ovary 2 0.3 4 1.1
Tubal pregnancy 0 00 4 1.1
Cancers 22 04 16 4.2
Brain/CNS 2 0.3 6 1.6
Bone 10 1.6 10 2.6
Abdomen 5 0.8 9 2.4
*Reproduced from Prabhakumari et al.5.
Table 7. Congenital anomalies*
Area I – Muliyar (sprayed) Area II – Banam (unsprayed)
N = 6107 N = 3742
Disease Number Prevalence Number Prevalence
Any organ anomaly (limbs + organ) 44 7 25 7
Congenital heart disease 23 5 19 5
Cleft lip/palate 6 1 0 0
Undescended testis 3 0.5 2 1
Hernia 25 4 12 3
*Reproduced from Prabhakumari et al.5.
couples who decide to terminate pre-
gnancies for fear of congenital abnor-
malities. Even if a few decide to flee
from this hell of a propaganda and social
stigma, after selling-off all their posses-
sions, the doors are shut as they will
have to sell everything at throw-away
prices. In short, irresponsible activism
and propaganda have made people refu-
gees in their own land. Well-facilitated
medical camps were conducted in all the
affected Gramapanchayaths during the
last two years and 4226 persons affected
by a range of about 350 diseases were
enlisted as victims of endosulfan spray-
ing. However, no criterion, including
clinical or biochemical, was applied for
the selection of these victims according
to the information obtained by the
authors through the provisions of the RTI
Act. Also, no guidelines were provided
by the Health Department for selection
of the so-called endosulfan victims.
Almost all types of common diseases
ranging from pulmonary bronchitis,
piles, polio, liver problems, skin dis-
eases, Alzheimer’s disease, dementia
(which is common among the old peo-
ple), etc. are included in the list. Persons
with congenital malformations who were
born before the commencement of the
pesticide spray as well as those who were
born 10 years after the stoppage of the
spray are included in the list of endosul-
fan victims. Persons residing at the bor-
der of the cashew plantations as well as
those residing 10–15 km away from the
estates have also ensured a berth in the
list of endosulfan victims. According to
the RTI information, Rs 734 lakhs was
distributed to the next of kin who alleg-
edly died due to endosulfan and Rs 66
lakhs is disbursed as financial assistance
every month to the alleged endosulfan
victims by the state government. People
with all sorts of alleged medical pro-
blems still throng the PHCs in thousands
for inclusion in the list of endosulfan
victims to get free medical aid and finan-
cial benefits. The people of an entire area
have been converted into government-
aid-dependent rather than self-reliant.
The present studies, flawed on many
counts, have only succeeded in adding
fuel to fire.
The allegation that there are increased
health issues in the endosulfan-sprayed
areas in Kasaragod is not proved conclu-
sively by any study till date. It is impor-
tant that the true picture of this allegation
that shook the conscience of the whole
world is brought to light. It is inevitable
that fears of the local people are dis-
pelled through a comprehensive, multid-
isciplinary epidemiological study.
Note
1. After submission of the manuscript, the
CSE has withdrawn this partial version of
the study report and substituted the same
with the unabridged version (ref. 5). Selec-

COMMENTARY
CURRENT SCIENCE, VOL. 104, NO. 1, 10 JANUARY 2013 21
tively abridged version published by the
CSE is now available at www.scribd.com/
116428426.
1. http://chm.pops.int/Convention/COP/
hrMeetings/COP5/COP5Documents/
tabid/1268/language/en-US/Default.aspx
2. http://www.ens-newswire.com/ens/may-
2011/2011-05-05-01.html
3. National Institute of Occupational
Health, Final report of the investigation
of unusual illnesses allegedly produced
by endosulfan exposure in Padre village
of Kasargod District (N. Kerala), 2002,
p. 98; http://endosulphanvictims.org/re-
sources/NIOH-FinalReport.pdf
4. Jayakrishnan, T., Prabhakumari, C. and
Thomas Bina, Part I Report of the com-
munity based study epidemiological
study of health status of population at
Kasaragod District. Kerala; Part II Re-
port of the school study. Epidemiological
study of health effects of endosulfan
among adolescent population at Kasara-
gode District. Kerala; Part III Report of
the estimation of endosulfan residues in
human blood at Kasaragod, 2011,
p. 16; http://www.cseindia.org/userfiles/
endo-study_brief.pdf
5. Prabhakumari, C., Jayakrishnan, T. and
Thomas Bina, Epidemiological studies
related to health in endosulfan affected
areas at Kasaragod District, Kerala 2010-
2011, Department of Community Medi-
cine, Government Medical College,
Calicut, 2011, p. 53; http://www.4shared.
com/document/UMOxBQvB/Endosulfan_
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6. Embrandiri, A., Singh, R. P., Ibrahim, H.
M. and Khan, A. B., Asian J. Epidemiol.,
2012, 5, 22–31.
7. Aravindan, K. P. (ed.), Kerala Padanam–
Keralam Engane Jeevikkunnu Keralam
Engane Chinthikkunnu? Kerala Sasthra
Sahithya Parishad, Calicut, 2006.
8. Centre for Science and Environment,
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*e-mail: sreekumarkmofficial@gmail.com
Solar energy for information technology: challenges and possibilities
Shrisha Rao and Pragati Agrawal
Information technology (IT) equipment is already estimated to account for about 2% of the global energy
consumption, and this figure is only expected to rise. However, the use of solar power for IT is yet to receive
the attention it deserves from researchers, and there is a vast array of important problems to be addressed
to enable the use of solar and other alternative energy sources in IT. In this note, we take the view that a
broad systems perspective of solar power generation and utilization (rather than looking only at component
technologies such as PV, solar-thermal, etc.) is essential, and mention major directions which in our opin-
ion merit attention in this regard.
With the worldwide increase in both
solar energy production as well as in the
consumption of energy by information
technology (IT) systems, especially large
data centres and such, it appears inevita-
ble that these two seemingly disparate
trends will soon interact in a much more
significant way than at present. It is
therefore necessary for us to understand
the likely manner of such an interaction,
and prepare to meet the challenges that
come with it. Some obvious points may
be noted in this regard:
• IT loads often have stringent avail-
ability requirements, coming to ‘five-9s’
(i.e. 99.999% uptime) or more.
• IT equipment and services cannot be
easily shut down or restarted, but unlike
other systems, IT jobs can sometimes be
(re-)located across great geographical
distances.
• Solar energy is subject to known
variations (hourly, seasonal, latitudinal)
that can be taken into account in some
cases.
It is thus of interest to consider how
solar generation systems (regardless of
the specific technologies used) can be
tuned to meet the needs of IT systems,
and how IT systems in turn can be built
to work with solar power. It could be
thought that networked systems such as
data centres are not in the proper pur-
view of studies of solar energy consump-
tion, but it should also be noted that with
new technologies and concepts such as
the ‘Internet of Things’, many systems
that were not commonly considered net-
worked are becoming so. Therefore,
studies based on concepts involving net-
worked systems can and do apply in the
analyses of large systems (even conven-
tional, non-IT systems) that are not usu-
ally thought of as being networked.
State of the art
It has been more than 50 years since the
first efficient solar cell was developed.