NEW DELHI: The Delhi Transport Corporation finds itself facing an unprecedented crisis of breakdowns. The corporation has admitted that 600-700 of its buses have been failing every day in the past few weeks - that's roughly one in every six DTC bus on the road and an unheard of breakdown rate of almost 16%.Add to that an average of 33 cluster buses that fail on the road every day and you get a picture of the breakdown epidemic facing the public transport system in Delhi, mainly on account of DTC's aging and inefficient fleet. Officials admit the corporation is so busy repairing its broken vehicles each day that services are hit."Around 600-700 buses on average break down each day. The reason is the weather conditions, which impact the engine," said DTC spokesperson R S Minhas. The engines were overheating in the high temperatures, especially in the air-conditioned buses, he said, adding, "The problem faced recurrently is that the engine cannot pull the load in the bus."Transport experts differ. S P Singh of the Indian Foundation of Transport Research & Training (IFTRT) says Delhi's weather conditions haven't suddenly changed. "These are manufacturing defects, and the entire fleet of low-floor buses has been facing problems since day one. The city's temperatures soar every year but you don't see other vehicles breaking down. Why do only buses break down? It's because these have inherent defects that need to be addressed," Singh claimed.Sources in DTC admit the break downs have gone up in the recent past. "Till last year, the average was between 350-400 buses every day. This has touched 600-700 this year," said an official. This number is only expected to go up each year as the fleet ages. In fact, sources in the Corporation say that the actual number of buses that break down is more than 800 each day - a staggering figure as it takes out around 15% of the fleet from daily service.According to official figures, 743 DTC buses broke down on June 17 and 705 the next day. AC buses accounted for around 300 of the total. This means roughly 25% of AC buses have been breaking down every day, since only around 1,200 such buses ply on the road. The fact that most other DTC buses plying on the roads are headed for scrap-having outlived their life- adds to the problem. Spare-parts for these buses are difficult to come by, thus leading to more break downs.DTC chief Debashree Mukherjee admitted the fleet faces a crisis. "We are working with the manufacturers to ensure the number of break downs come down," she said.Mukherjee said a "special" maintenance schedule has been drawn up in the past fortnight. "We are closely monitoring the maintenance procedure. Under the new schedule, 10 buses from each depot are taken out for an exhaustive full check-up and over-hauling, which is beyond the regular maintenance," she said.Mukherjee said the new schedule had led to a reduction of 10% in the number of break downs in the past week. S P Singh, however, said these measures were just addressing the symptoms but not the disease. "The load and speed ratio contributes to over-heating of the engine. The engines, especially on the AC buses, cannot handle the load," he said.