Three persons were booked in two incidents of alleged violation of noise norms for relaying azaan from mosques using loudspeakers before 6am, Mumbai police officials said on Saturday.

The first case was registered when azaan was relayed at 5:15 am using a loudspeaker from Nurani Mosque in Bandra West on Thursday, which is a violation of Supreme Court directives that ban noise pollution between 10pm and 6am, an official said.