The Kerala High Court in southern India has reinstated a ban on the highly hazardous pesticide endosulfan, already banned in many countries, after growing concern at the risk of farmers and villagers being poisoned.
The news comes as an unpublished report, seen by the BMJ , shows the impact on villagers in the area.
At the behest of India's National Human Rights Commission, the Indian Council of Medical Research last year asked the National Institute of Occupational Health to investigate the pesticide's effects. The institute's report, finalised in March 2002, still remains confidential.
The report shows that water samples collected by the institute some 10 months after spraying with endosulfan in the village of Padre, Kerala, still showed residues of the pesticide.
Although the concentrations of the pesticide were below the US Environmental Protection Agency's recommended maximum, the report warns: "Detection of even very small endosulfan residues signifies continuous exposure of the population since the spray began more than 20 years back."
India's pesticide industry is the fourth largest in the world. India is the largest producer of endosulfan, a pesticide that can affect the central nervous system and is dubbed "highly hazardous" by the US agency.
The controversy was first brought to light by the Centre for Science and Environment, Delhi, which conducted laboratory analysis of samples from Padre collected two months after spraying of cashew nut crops. The analysis showed that the concentration of endosulfan was 7-51 times higher than the maximum limit. In one sample the concentration was 391 times higher than the maximum.
The centre's director, Sunita Narain, described the findings as "frightening."
The current, unpublished National Institute of Occupational Health's study compared the effects of endosulfan in 170 children exposed to the chemical and 92 control children. Compared with the controls, a higher proportion of the exposed children had a low IQ and poor performance at school.
It also looked at learning disabilities among 619 exposed children and 416 controls, a tenth of the children (66) exposed to the pesticide had learning disabilities, compared with 3% (11) of the control children.
The overall prevalence of congenital abnormalities, such as congenital heart disease and skeletal abnormalities, was also higher among the exposed children.
The study did not specifically implicate endosulfan but asked for more detailed studies of factors causing genotoxicity. It added: "Significantly higher prevalence of congenital malformations in the exposed group points to some genotoxic agent, which in the present study could be endosulfan."
The state government had last year banned the use of endosulfan, but under intense pressure from the pesticide industry the ban was lifted in March 2002.
Kerala's health secretary, Mr K Ramamurthy, said the state government had no data indicating that the health effects are caused by endosulfan. "Nobody is sure and the information is all preliminary, but we are looking into it," he added.
Meanwhile a report by three non-governmental organisations, The Killing Fields , concludes that pesticide poisoning could account for more than 500 deaths in the Warangal district of Andhra Pradesh between August and December 2001.