Illegal construction

Sir, I'm Rajesh podder from north 24 parganas ,kolkata. facing problem about illegal construction of my neighbour . He has constructed a permanent garriage without leaving any space from my boundary And without any valid municipal sanction plan. I complained to our municipality against this illegal construction.After enquiring of the site by municipality engineer authority issued a notice to stop the illegal construction . But the owner continued the construction & completed . I informed the municipality for violating the notice but they did not take any action. After one month when i send a reminder letter to the chairman of the municipality , He send his engineer to visit the site .and send a letter for appearing at municipality and where the chairman fined that owner ( who construct the illegal construction ) & legallised the matter .My question is that can the chairman do it lawfully ? If not , what can i do now ? Is there any court order about this illegal construction . Pl. help me about this matter .