Evidence cited by S K Kabra from his field studies allegedly indicates a strong circumstancial correlation between peak usage of chemical pesticides and appearance of ntds suffers from the following shortcomings.

- Statistically speaking, the incidence is not higher in the months as alleged by him.

- No specific toxic agent(s) have been identified as the cause(s) of the alleged increase in incidence of ntds.

- No experimental research supporting the alleged teratogenic effects of any of the pesticides is incorporated.

- Pesticides as the sole, or major cause, of folic acid deficiency has not been established. Even the presence of folic acid deficiency has not been documented.

- As the author himself says, village folk rarely use the vegetables grown using high pesticides whereas the converse is truer for city folks. From the data presented it is not clear if ntds occurred more frequently in village or in the city people. A lot of village people do go to cities for delivery purposes as facilities at village level are often very deficient.

- There is no evidence to suggest that vegetables grown during the period of high intensive use of pesticides have a higher percentage of the pesticides and, if so, in what form. A certain degree of change does occur during plant metabolism.

- The contention of some of the quoted health administrators, that is the director and secretary of health services of Rajasthan, that as the report is from a private source and not a governmental source and, therefore, less reliable, is to say the least, untenable. Scientific reports are either accurate or inaccurate and not governmental or private. They have to be judged with strict scientific mind and not on the basis of organisations.

- Lastly, Kabra shares the concern with many people that increasing use of pesticides is linked to various diseases, which manifest themselves at the time of birth or later. However, for a proper scientific understanding of the link, more rigorous methods will have to be used than this one employed by Kabra.

Anil K Singh
Professor of neurosurgery, G B Pant Hospital, Delhi University

The most striking fact in the article is the argument in favour of pesticide residues being the culprit. I would be more cautious because the case is not sufficiently close to be convincing