At least 21 people have drowned after a double-decker tourist boat capsized in India’s southern state of Kerala, local authorities have said, The Guardian reported.

The boat was carrying about 40 inbound passengers when it overturned off the coastal town of Tanur because it was overcrowded, said Abdul Nazar, Malappuram district’s junior superintendent of police.

Most of the victims were children on school holidays, Kerala’s minister for fisheries and harbour development said. V Abdurahiman told reporters the death toll from the tragedy on Monday was likely to rise as the boat was stuck in muddy waters and was being pulled out to rescue those trapped inside.

About 10 passengers were being treated in various hospitals, Nazar said. Four people were taken there in a critical condition, the PTI news agency quoted Abdurahiman as saying.

Survivors told local media that many of the passengers were not wearing life jackets, according to The Guardian.

Monday has been declared a day of official mourning, PTI reported, quoting a government statement.

The incident in the Malappuram district took place at about 7pm local time on Sunday and a team from the National Disaster Response Force was at the site, a Kerala State Disaster Management Authority spokesperson said.

India’s prime minister, Narendra Modi, said in a tweet he was “pained by the loss of lives” and announced compensation for the victims’ families.

Boating accidents are common in India, where many vessels are overcrowded and have inadequate safety equipment, The Guardian reported.

In September 2020, 12 people drowned when a sightseeing boat capsized on the swollen Godavari River in the southern state of Andhra Pradesh. In May 2018, 30 people died when a boat capsized in the same region.