At least 11 people died in Madhya Pradesh’s Sultan Garh waterfall in Gwalior after dam water was released at the popular tourist site, ANI reported. A rescue operation is underway to help the 40 people who are believed to be stranded at the site in Shivpuri district. Eight people have been rescued till now, Shivpuri Collector Shilpa Gupta told News18.

Some reports, however, attributed the situation to a consequence of the rise in water levels following heavy rain.

Superintendent of Police Rajesh Hingankar said that an Indian Army helicopter was being used in the rescue operation, India Today reported. Low visibility at night is hindering the rescue efforts by the state and National Disaster Response Force.

Gwalior MP and Union minister Narendra Singh Tomar said he visited the site to take stock of the situation. “Efforts underway to rescue those stranded. I am in touch with the rescue teams,” Chief Minister Shivraj Singh Chouhan tweeted.