Deshbhakt
I don't know if this law has been effected or is being applied
BUT I doubt it very much if it can be implemented effectively in Tanzania. There are many reasons (moving parts) why this law will be difficult to implement:
1. Technical.
The threshold levels of decibels at the source and at the complaining party can be debatable and easy to fudge, let alone having enough officers/equipment to patrol. Most of the time it will depend on complaints from citizens.
2. Social.
Most of these offending parties (night clubs, places of worship, etc.,) are legitimate business with legal permits to carry out their activities. Short of zoning them out (banishing them to the extreme city limits) and create a social uproar, it will be hard to tell a night club to whisper their stage music.
3. Law enforcement.
With rampant corruption and corrupt officials, this exercise can be an uphill struggle. It will be akin to expecting our traffic police to bring down the carnage in our roads.
Anyway, the short answer to both of your questions is
I DON'T KNOW. Sorry.