INDIA'S national capital, which adds an estimated 960 new vehicles to its roads daily, is mulling over a ban on diesel-powered cars to check an alarming rise in pollution - a problem it had successfully licked a few years ago.

Delhi in 2003 won the US Department of Energy's first Clean Cities International Partner of the Year award for "bold efforts to curb air pollution and support alternative fuel initiatives".

This came after the city administration drove polluting industries out, compelled truck and bus operators to switch to compressed natural gas and banned trishaws and taxicabs older than 15 years.

As a result, compared with 1997, carbon monoxide levels came down 32 per cent and sulphur dioxide as much as 39 per cent.

Delhi residents could again see the winter sun where smog once used to envelop the capital, blocking sunlight.

But those gains are poised to be reversed, no thanks to a massive increase in vehicles, an increasing proportion of which are powered by diesel engines which are cheaper to run by a third but emit several times the pollutants spewed by leaner-burning petrol cars.

By some accounts, breathing Delhi's air is equivalent to smoking 20 cigarettes a day. The haze has been back this winter.

The capital currently has 5.4 million registered vehicles and that number is increasing by 963 vehicles a day. Of this number, 350 are cars.

Much like Beijing, which is mindful of its pollution record ahead of next year's Olympics, New Delhi, which will host the Commonwealth Games in 2010, is preparing to tackle the problem.

"We will come down with a strong hand and ban the registration in Delhi of diesel vehicles if everything else fails," Mr J. K. Dadoo, Delhi administration's Secretary for the Environment told a meeting of auto manufacturers on Monday.

"Delhi can ban the use of any fuel it chooses. We have the legal powers."

Delhi Chief Minister Sheila Dikshit says pollution checkposts will also be put up at the 19 entry points to the capital. Non-Delhi vehicles entering the city will be checked and those breaching emission norms will be turned away.

Such moves, which are bound to face court challenges if attempted, are typical of a country which ignores solutions that stare it in its face and then turns to harsh measures when the crisis inevitably develops.

New Delhi is building a world-class metro rail, but it is two decades too late. Meanwhile, the surging Indian car industry is set to get a boost when the Tata group rolls out what it calls a "Rs 1-lakh (100,000 rupees or S$3,700) car", targeting scooter and motorbike users looking to move up to bigger vehicles.

In the 2006 annual budget, Finance Minister P. Chidambaram gave special incentives to small-car manufacturers.

Days later, in an Asia Interview to this newspaper where he was asked if his priority should not have been public transportation, he defended his move, saying India could not be expected to take "Singapore-style solutions".

"We are talking of transportation in the countryside also. Should not people in the countryside own cars here? Singapore does not have a countryside, it's not comparable," he said.

Global manufacturers have crowded into the Indian market, eyeing the widening middle income groups in the nation of 1.1 billion people.

Riding on an economy expanding at near double-digits, car companies sold a total 1.75 million cars last year, a 22 per cent increase from 2005.

Thanks to the base provided by the huge domestic market, companies such as Hyundai and Suzuki are planning to use India as a global platform to manufacture cars, recent press reports have said, citing company officials.

Suzuki, the No. 1 carmaker in India, last year set up a new diesel-engine plant in India. In January, it launched a diesel-powered version of its popular Swift subcompact.

For every company, the top market is New Delhi, a reason carmakers cannot ignore the policy actions of the federally administered territory.

Car manufacturers say they cannot be blamed for the ills resulting from the rapid growth of private transportation.

Besides, they point out, a reason why some cars pollute more is because many petrol stations use adulterated fuel to raise profit margins on fuel sales. Even the legitimate fuel could have higher refining norms.

"I don't think industry will have a problem agreeing to Euro 4 norms if the right fuel is available," Mr Prakash Sardesai of BASF, which makes emission control devices, said at the meeting called by the Delhi administration this week.