These findings were summarised in a briefing paper circulated by the Centre for Science and Environment (CSE) at the National Conference on Health and Environment here today. The paper, quoting studies by institutions like AIIMS, points out that though the use of DDT has been banned in agriculture, breast milk samples from Delhi show that DDT levels had not declined over the past decade, and were comparable to those found in Punjab, an area of intensive farming.

Worse, the Central Pollution Control Board (CPCB) has established the presence of DDT residues at 16 locations along the Yamuna, Delhi's only drinking water source. Clearly, DDT, like any other pollutant, doesn't stay confined to one geographical location, and once it enters the human body, it stays on like an unwanted guest in the fat cells.

But DDT is not the only noxious substance floating in the air. The only Indian study on benzene pollution done till date, has shown that the presence of this blood cancer-causing substance in the air we breathe is 12 times higher than European levels. This is because Delhi has 17.4 lakh, or about 7.5 per cent, of the country's two-wheelers equipped with the deadly two-stroke engine.

These two-wheelers allow 20-25 per cent of the petrol in their fuel tanks to escape unburnt. And unburnt petrol is the richest source of benzene. That may be the reason why the incidence of blood cancer in Delhi is 1.5 to two times more than the numbers reported from Mumbai, Chennai and Bangalore, and more than two times the level of Bhopal. It is to stop this count from going up that experts at the conference have pleaded for a vehicle taxation policy favouring zero-emission two-wheelers that use batteries or fuel cells.

The city's law-makers, meanwhile, appear to be impervious to the air they breathe. According to the CPCB, the Town Hall, or the headquarters of the Municipal Corporation of Delhi, is one of the two most polluted parts of the city, the other being Najafgarh.

And this apathy shows in the rising levels of all pollutants, despite the heightened environmental consciousness in the city. A study by Manoj Dhingra of the Department of Anatomy, AIIMS, shows that the average levels of suspended particulate matter had risen from 373 micrograms per cubic metre in 1989 to 407 in 1995; that of sulphur dioxide, from 8.7 to 19; and of nitrogen dioxide, from 18.5 to 34.1. Clearly, as CSE chief Anil Aggarwal put it, quoting Delhi Government Transport Minister Rajendra Gupta: ``Politics and pollution don't mix.''