Around two dozen cars crashed into each other in the season's first vehicle pile-up on the Yamuna Expressway on Wednesday morning, injuring at least eight Delhi residents as blinding haze enveloped Delhi and the National Capital Region.The pile-up at Dankaur near here began after a car ran out of fuel and stopped suddenly on the expressway, that links Noida with Agra, Investigating Officer Anand Kumar told IANS.He said some 24 vehicles driving towards Delhi were involved in the accident and that eight injured persons from the capital were wounded. They were given first aid at a hospital and discharged.The collision spot was near an under-construction eastern peripheral flyway, which had been barricaded off, but the dense fog made the barricades invisible, and cars rammed into it, leading to the pile-up. Traffic was halted at the stretch for a few hours before two cranes cleared the crashed vehicles."The visibility had reduced drastically due to heavy smog. It was almost blinding. Drivers could not see beyond a certain distance, they may have applied brakes but it may have been too late to control their cars and the vehicles hit each other," said Farmood Ali, station house officer at Dankaur police station.He said there are reflectors but drivers could not see the barricades on the stretch due to low visibility and ran into them. "All the vehicles hit bumper to bumper."Ali said over-speeding and frequent lane changing in foggy conditions usually makes driving on the busy stretch of the highway more dangerous.He said at an average 30-35 accidents occur in every winter season due to fog.Some 1,600 accidents were reported on the eight-lane 165-km toll road in 2016 -- twice more than the 800 in 2014.