The Calcutta Municipal Corporation will seek funds from the Asian Development Bank (ADB) to build a sewer network in 11 wards that has open drains, mayor Firhad Hakim has said.

Hakim said on Saturday he would seek the funds at a meeting scheduled later this month.

The wards with open drains — 108, 109, 125, 126,127, 139, 140, 141, 142, 143 and 144 — are in Jadavpur, Behala and Joka.

The open drains are “poorly planned with inadequate depth and width, improper slope and discharge point”, a civic official said. All these factors lead to waterlogging.

The CMC is planning a new underground drainage network to help drain out rainwater faster, the civic official said.

The civic body will also build sewage treatment plants to keep the toxicity of the effluent within permissible limits and ensure it does not pollute canals, the official said.

“A meeting with the ADB is scheduled for March 26. We will ask the bank for help to replace open drains with an underground network,” Hakim said on Saturday.

While most of the 11 wards have certain stretches with open drains, there are a few that don’t have any covered drain at all, another civic official said.

The ADB has given more than $650 million in loans to the CMC for the Kolkata Environment Improvement Project (KEIP) over the past several years.

The KEIP has built sewers in several places, but many areas are still to be covered, the official said.

The state government and the CMC, too, helped with funds.

The civic official said the ADB had written to KEIP, seeking an audience with mayor Hakim.

“The open drains are of inadequate size in many places, a reason why water doesn’t flow well through them, triggering waterlogging. Also, people throw garbage into the open drains that clog them,” a civic engineer said.