From a Press Release by Yorkshire Water:

Trillions Of Fat-Busting Bugs To Be Deployed To Help Fight Sewer Fat

Trillions of fat busting bugs are being deployed from today (Thursday 22 December) by Yorkshire Water over the festive period as it bids to rid its sewers of fat blockages and prevent pollution.

... with Christmas just around the corner, when the company typically sees a 25% increase in the number of fat blockages it deals with, the company is unleashing an innovative biological weapon as part of its ongoing campaign to reduce the amount of fat in its sewers and, subsequently, the risk of sewer flooding and pollution events in the region.
"The deployment of fat-busting bugs in our sewer network is an example of this, with these 'good' bacteria literally feasting on solidified fat in our sewer. And because these bacteria constantly multiply in the right environment, we can leave them to get on with their job in our sewers, seven days a week, 24 hours a day, without the need for regular dosing.

Ee, my bugs!