Its 11 in the night on the busy Delhi-Jaipur highway at the Delhi-Gurgaon border on National Highway-8 as trucks start lining up to enter the capital.According to Municipal Corporation of Delhi or MCD estimates, 80,000 trucks enter the capital every night. Concerned with the heavy pollution caused by trucks, the Supreme Court had in 2001 ordered all trucks not destined for Delhi to bypass the capital. The reality is however very different as NDTV found out.We tracked several trucks as they crossed over the MCD toll barrier at various border posts in the capital. Not one truck was checked for pollution or its final destination. We even travelled in one truck coming from Mumbai and headed to Gajraula in Uttar Pradesh as it made its way through Delhi.The driver told us that he was using the route through Delhi as it was shorter by 40 kilometres and was hopeful of being able to 'convince' any policemen who were to stop him. Traveling in the truck, we passed several check posts but no one seemed to stop and ask the driver for his final destination.Back at the Delhi border, one driver who was on his way to Punjab from Ahmedabad said, "In Delhi trucks may pass 8-10 check posts. It is up to the drivers how they talk to the inspectors. Usually Rs 50-100 works and they get through.""It's like firefighting... Even if you stop one truck for a few moments there will be a traffic jam for miles, so it is difficult to enforce. The problem is also the fact that the states don't have enough manpower and truck drivers can intimidate them so they let them through," admitted Bhure Lal, the Chairman of Environment Pollution (prevention & control) Authority (EPCA) in the capital.Mr Lal is trying to get the Centre along with Delhi, UP and Haryana government to expedite two expressways - one either side of Delhi - to ensure transit traffic does not enter the national capital.The Kundli-Manesar-Palwal or KMP expressway was to have been completed by 2009; it's already way over schedule and the budget has shot up from 1900 crores to more than 3600 crores. Work on the eastern expressway hasn't even started and only remains on paper. This expressway starting at Kundli will link Ghaziabad to Palwal. Years of delay have pushed up the cost from 3000 crores to 6000 crores.The Supreme Court has said that it will not allow for any delays or extensions. While the KMP expressway has to be ready by July next year, the eastern expressway will have to be ready by 2018.Delhi's notoriously polluted air quality has been in the headlines for some time especially after the World Health Organisation or WHO last year ranked the capital with the worst air quality among 1600 cities across the world."The daily influx of trucks in the capital is an enormous contributor to particulate load and Nitrogen Oxide, and a leading cause of respiratory and other diseases," says Anumita Roy Chowdhury, executive director with Centre for Science and Environment or CSE.While it takes a truck about an hour and a half to go through Delhi, unless enforcement is increased, they will continue to drive through the capital leaving behind their deadly cocktail of noxious fumes.