Indian singer-composer Zubeen Garg's drowning last year in Singapore was accidental and there is no evidence of foul play, a coroner's inquiry has found.

Garg, 52, died on 19 September after drowning in the sea off Singapore's coast. The inquiry report says he was intoxicated at the time of the incident.

The singer's sudden death sparked anger and distress among millions of fans in his home state Assam, and set off a wave of mourning.

It also became a politically charged issue, with Assam's Chief Minister Himanta Biswa Sarma calling it "plain and simple murder". He hasn't offered any evidence to support his allegation, but seven people arrested in connection with the case remain in custody.

Police in Assam have charged four of them, including Garg's manager, with murder. All seven have denied any wrongdoing.