By end 2009, India will set a uniform limit for pollution across the country, making no distinction between industrial and residential areas, sources in the ministry of environment and forests said.

At present, for instance, the amount of ‘Respirable, Suspended Particulate Matter’ (RSPM), a major pollutant, allowed in industrial areas is 120 unit grams per cubic metre (ug/m3), while the maximum tolerated in non industrial ones is only 60 ug/m3.

While earlier, industrial areas were usually located far away from residential ones in most cities, this is no longer the case. Both residential colonies and industries have expanded until they stand cheek by jowl.

“When the national ambient air quality norms were notified in 1994 most industrial areas were away from residential areas,” said a top environment and forest ministry official. “Now this is not the case. There cannot be two different air quality standards for citizens living side by side.

The two adjoining west Delhi suburbs of Janakpuri and Mayapuri are both equally polluted with RSPM levels of around 240 ug/m3. Janakpuri, however, is categorised a non industrial area, and Mayapuri, an industrial one. Thus the air in Janakpuri is regarded as four times more polluted than permissible — indeed Janakpuri is often cited as the most polluted area of the city — while Mayapuri is seen as only twice as polluted, though the residents of both localities are breathing much the same quality of air.

Of the 342 locations monitored by the Central Pollution Control Board, RSPM levels were higher than the norm in 78 per cent of the industrial areas and 87 per cent in the residential areas. What this conceals is that RSPM level in almost all industrial areas were higher than that in the residential zones.

For residential areas, the new norms are expected to remain same but the industry would have to adhere to more stringent norms. “Industry clusters will have to invest on pollutant trapping technologies to improve on overall emissions,” the official said.