Kolkata’s drainage system is what Britisher’s developd before freedom and after that there is not much of work that is done but good news s that Kolakat Municipal Corporation has decided to upgrade the existing sewage system to meet water logging problem during rains like they had also decided to make Kolkata Roads to be water proof before Pooja. KMC is already using water drainage pumping station during heavy rains and now more modern tools will be included.
KMC received RS.500 crore under JNNURM ( Ministry of Urban Renewal Mission ) for the rehabilitation of 24 km of man entry brick sewers and 36 km underground non-man entry sewers. The renovation of the man-entry sewers and the Infrastructure establishment of both man-entry and the non man-entry sewers have shown a noticeable improvement in the speed of drainage of storm waters.

Kolkata Environmental Improvement Project-(KEIP) is a multi-agency endeavour to arrest environmental degradation and improve the quality of life in Kolkata. Its work is mainly in the outer areas of the city where the sewerage and drainage infrastructure is grossly inadequate and the drainage canals are choked by silt.
Source :- The Telegraph Kolkata