The NGT order had come on a petition filed by a young lawyer, praying for the court's interference in improving Delhi's notoriously dirty air. Over 14 hearings later, in which all concerned Delhi government departments and Union ministries have marked their presence in the court, the ban is nowhere near implementation.

The Ministry of Road Transport and Highways (MoRTH) has already presented three different reports from Indian Institute of Technology, Delhi University and University of Birmingham to prove the green panel order futile in the long run. The case is now set to be heard after NGT returns from its summer vacation on July 13. Delhi, meanwhile, continues to suffer due to increasing number of vehicles - both old and new - and the air gets dirtier each passing day.

Senior advocate Sanjay Upadhyay, appearing for the applicant Vardhaman Kaushik, says, "The government has indeed shown much reluctance to come up with anything concrete. They have been looking for excuses to not enforce the ban on old vehicles. The response to the court's directions has been more in denial mode than acceptance."

Another problem is lack of coordination between agencies, he points out, "NGT Chairperson Justice Swatanter Kumar is making the departments sit down together and discuss ways out. The bench has indeed segregated the bulky problem in a very systematic manner, going by source - vehicular, garbage burning and industrial. This is a really good way of moving ahead."

Experts are divided on the immediate measures that can be taken to tackle the crisis. The only comprehensive air pollution source apportionment study done in Delhi so far, by the Central Pollution Control Board in 2007, has been trashed by its commissioning body, the Ministry of Environment and Forests (MoEF) itself. The report concluded that 60 per cent of the air pollution caused in Delhi is by vehicular traffic. Additional Solicitor General (ASG) Pinky Anand told NGT on Monday, "We do not agree with the CPCB report." She told Mail Today, "It's an old report and did not have enough data."

The argument the ministry has been pushing for is that taking off 29 lakh petrol vehicles that are over 15 years of age - both government and private - from Delhi's roads is unfeasible and would not serve the purpose. Also, the diesel guzzling trucks which ferry essential goods - milk, fruits, vegetables and grains - between Delhi and other states daily cannot be made to disappear overnight.

Researchers working independently, however, say that it is simply "misleading" the court and the public to attribute pollution to sources other than vehicles. Anumita Roychowdhury of the Air Pollution and Clean Transportation programme, Centre for Science and Environment, says, "In a bid to protect old cars, the science of exposure risk to deadly vehicular pollution has been played down in the IIT Delhi-Transport Research and Injury Prevention Programme (IITD-TRIPP) studies cited by the Ministry of Road Transport and Highways. There is enough evidence to prove significant contribution of vehicles to multi-pollutant crisis in Delhi and justifies the strong action demanded by NGT."

At the same time, she adds, "The reports only talk about Particulate Matter 2.5 and not other toxic fuel combustion products like Nitrogen Oxides and Volatile Organic Compounds. Diesel exhaust has been classified as a Class I Carcinogen by WHO and International Agency for Research on Cancer (IARC)."

Delhi, meanwhile, continues to pile on vehicles and layers of toxic pollutants. Already crowned the world's most polluted city in terms of air quality, it adds 1,400 cars to its roads every day. In the last decade, the number of vehicles in Delhi has jumped by 97 per cent.

In 2000, diesel cars accounted for only four per cent of all car sales. Now half the cars sold survive on diesel. Public transport has not been able to keep pace. Despite a Supreme Court order saying Delhi should have 11,000 public transport buses, roughly 6,251 are in service.