Are you able to make changes to the flat ? One very good way reduce noise from the street is to replace the windows with new windows with 2 or 3 layers of glass in well sealed new window frames. Another way is to add a layer of drywall to the front wall with an airspace between the original wall and the new drywall panels using a metal channel. If it is a rental and you can't make changes, keeping the windows closed is the best thing that you can do.

No, its not suggestive unless and until your get the seepage repaired. If its not repaired and tiled then the seepage will get diverted to some other wall .

Unpolished, unfinished wood planks, glass wool (use as last resort), or nylon fiber are three alternatives which can be used to seal gaps. Thickness of floors, walls also matters for sound to radiate through. Cheapest alternative is of course paper as the best sound absorbent paper. Unlaminated newsprint is the best.

hi, frnd, what is the solution for these dump walls pls help with regards Neetu