Just when you thought the subways couldn’t smell any worse.

A woman was photographed setting her hair on fire aboard an MTA train Tuesday.

The snap, posted to Reddit, shows the unidentified woman taking a lighter to her long, multi-colored locks while casually seated aboard the train.

The photo is undated, but a copy of Tuesday’s Metro New York sitting at her feet proves it was taken Tuesday.

One poster on the message board suggested the woman was fusing together the ends of a weave.

The MTA did not immediately return a request for comment.