Curry houses are being encouraged to recycle their cooking oil and cut the amount of fat being poured down drains.
Thames Water clears up to 10,000 blockages every year
Ealing Council has written to 100 restaurants urging them to sign up to a three-month pilot project which turns unwanted oil into biodiesel.
Waste oil will be collected for free and taken to one of two processing plants in north London and Kent.
It is hoped the scheme will tackle the problem of fat blocking sewers and reduce the number of rats.
Thames Water said it clears up to 100,000 blockages every year as a result of fats, oils and greases being put down drains.
It also estimates a 25% increase in the amount of fat ending up down drains over the Christmas period.
Ealing Council's Will Brooks said making the streets cleaner was a main priority.
"This service can benefit everyone involved, it's free and encourages businesses to do their bit for the environment.
"Throwing oil down drains helps block sewers, which can then lead to flooding, and makes waste water treatment more costly."