An offence was registered against40 persons from the Muslim community who allegedly defied the COVID-19 lockdown by participating in a religious ritual in south Mumbai's Dongri area, police said on Thursday.The incident took place on Wednesday at Banatwala Building, where two flat owners organised the observance of 'Maatam', a ritual performed by Muslims, an official said.At least 40 persons, including women, had participated in the ritual and a case was registered against them under relevant sections of the Indian Penal Code and Disaster Management Act, he said.The police have also served notices to the organisers under the Criminal Procedure Code, for holding an event despite the prohibitory orders, which were in place to contain the spread of COVID-19.