Each resident of Delhi is familiar with it. And when friends and relatives from the smaller cities and towns of India come visiting, they hardly miss an opportunity to remind the residents of the extreme pollution in the capital. The time has now come for Delhiwallahs to start pointing out that the air of most smaller cities and towns in India is as polluted as Delhi, or is fast becoming so, even if it does not attract wide public attention. And if they scoff at it, wave some ambient air quality data from the Central Pollution Control Board (cpcb), New Delhi, under their noses (see graph: As polluted as Delhi, and getting worse). They will surely think about returning with a gas mask or two.

In 1997, an air quality monitoring station in Lucknow, the capital of Uttar Pradesh, recorded the maximum level of suspended particulate matter (spm) at 2,339 microgrammes per cubic metre (