NEW DELHI: Authorities in the Indian capital are launching a new crackdown on polluting traffic in a further bid to clean up one of the dirtiest cities in the world.

After forcing buses and auto-rickshaws to switch to clean compressed natural gas (CNG) in 2002, fears are growing that those gains are being kocked over by the ever-growing number of vehicles on the roads, and particularly those burning cheaper diesel fuel.

But Rajeev Talwar, Delhi's transport commissioner, has announced tough new penalties for vehicles causing excessive pollution. "Starting February 1, we are launching an intensive drive against vehicles emitting visible pollution," he said.

"Owners will be fined 1,000 rupees (22 dollars) and the second time their vehicles will be impounded. Any polluting vehicle coming into Delhi from nearby areas will turned away."

Additional personnel posted at checkpoints on Delhi's borders would ensure no polluting vehicle enters the city, he said. It's fighting talk and, given India's legendary corruption, demands determined policing to succeed.

Stand on the major intersection linking Delhi's ring road with the clogged main artery to Taj Mahal town Agra and the number of vehicles spewing out thick, noxious smoke is terrifying.

More vehicles seem to be emitting foul dark fumes than not. At night, when big, antiquated trucks re-supply the population of 14 million, the air around the Ashram flyover is so thick your nose can tingle and eyes turn red as you cough up greyish-black phelgm.

"We will make it compulsory for commercial vehicles to be serviced once in three months. Any certificate which shows that the vehicle is not serviced once every quarter will be impounded," Talwar said.

"From April 1, only Euro-III compliant vehicles will be registered in Delhi," he added. An international clean air conference in Agra last month noted that New Delhi not only topped the list of highly polluted Indian cities but rivalled Mexico City as the capital with the worst air in the world.

Levels of suspended particulate matter hit 10 times World Health Organization recommended levels in Delhi and spiked at far worse. A minister told the conference five million Indians die every year due to air pollution.

India has about 66 million vehicles on its roads with seven million added just last year, according to the Society of Indian Automobile Manufacturers. However Talwar claimed pollution had come down "considerably" since the introduction of CNG.

"The Central Pollution Control Board (CPCB) has found that whether it is suspended particulate matter, respiratory suspended particulate matter, sulphur dioxide or nitrogen dioxide, the levels have come down in the past two years.

"No doubt CNG is a much cleaner fuel and 55,000 auto rickshaws in the capital and 13,000 buses are now on CNG," he said. Vinod Kumar Gujral, a doctor treating cardiac and respiratory diseases in Delhi said the number of cases of chest infections, asthma attacks and respiratory allergies had declined in the past two years. "No doubt this is due to the effects of CNG," he said.

Environmentalists too vouched that Delhi's air quality had improved - due to the introduction of clean fuel, relocating polluting industries out of Delhi and switching from coal to gas-based power plants. -AFP