Six people were injured on Wednesday when over a dozen speeding cars rammed into each other on the Yamuna Expressway in the National Capital Region, where poor air quality has led to a dense smog cover since Tuesday, the Hindustan Times reported. The accident took place due to low visibility in Greater Noida’s Dankaur area, the police said.

The collisions occurred on both sides of the expressway at a spot where barricades were put up since construction work is going on. “People could not see the barricades due to low visibility and ran over them,” a police official told the Hindustan Times. “All the vehicles hit bumper to bumper.”

Seven of the 13 cars involved are still at the spot while the other six left soon.

A Twitter user posted a video, which he claimed was of Wednesday’s incident on the Yamuna Expressway.

Earlier in the day, at least 10 people were run over by a truck travelling through thick smog in Punjab’s Bathinda. The group was waiting for a vehicle after the bus they were travelling in broke down, Senior Superintendent of Police Naveen Singla told Scroll.in.

Pollution has risen to alarming levels in Delhi and the surrounding areas. The Indian Medical Association had declared a public health emergency in the Capital on Tuesday.