The problem of sound pollution can be solved if any of the following three things happen -
1. If electricity supply company starts supplying electricity 24x7, there will be no need of using genarators
2. Subject to financial and techical feasability, alternate means of silent electricity generation like solar energy or inverters etc are used.
3. Subject to financial and techical feasability, better type and quality silencers are installed on the existing generators to reduce sound pollution.
Since you have already complained to the local Pollution Control Board, you must be having copy of complaint with proper official sign and stamp with you. If Pollution Control Board has done nothing, file RTI to know what steps they have taken on your complaint. Then sit with a local lawyer of unshakable integrity and repute to take the matter in High Court in form of writ to direct the Pollution Control Board to take appropriate steps as per law.