A poorly maintained and overcrowded bus veered off the road and plunged into a deep gorge in northern India on Monday, killing at least 36 people and injuring several others, officials said.

The accident occurred in Almora district in the mountainous state of Uttarakhand. The bus was carrying around 60 people, and more than 20 have been injured, said Deepak Rawat, a senior state government official.

Authorities said earlier they believed there were 42 passengers, which was how many people the bus could accommodate.

Teams of rescue and relief workers were deployed to the site and officials feared the death toll may rise further, especially as seven passengers in hospital were in critical condition.

Television footage showed parts of the bus mangled and destroyed as it lay overturned on a rocky slope, close to a stream. Rescuers were seen working to pull out passengers and carrying bodies on stretchers.

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The state’s chief minister Pushkar Singh Dhami earlier said rescue teams were working to quickly evacuate the injured passengers to nearby hospitals and that authorities have been instructed to airlift those seriously hurt.

The state government has opened an investigation into the accident, said Vineet Pal, another official in the state. He added that preliminary information suggested that the dilapidated bus skidded before tumbling down a 60 meter- (200-foot-) -deep gorge.

A number of passengers managed to escape or were thrown out by the impact, and then alerted authorities about the accident. Two transport officials have been suspended for approving a bus that was in poor condition, Pal said.

India has some of the highest road death rates in the world, with hundreds of thousands of people killed and injured annually. Most crashes are blamed on reckless driving, poorly maintained roads and aging vehicles.

In July, at least 18 people died after a double-decker passenger bus collided with a milk truck in Uttar Pradesh state. In May, a bus carrying Hindu pilgrims skidded and rolled into a deep gorge on a mountainous highway in Indian-controlled Kashmir, killing at least 21 people.