NEW YORK (WABC) -- New York City Mayor Bill de Blasio and MTA Chairman Joe Lhota are at odds after the transit agency floated the idea of banning certain food on the subway to prevent track fires.Lhota vowed to step up the agency's efforts to prevent fires on subway tracks after commuters were treated to a nightmarish commute Monday thanks to trash that caught on fire in Harlem.The mayor responded by saying eating on the subway is a crucial time-saver for many New Yorkers and that a ban just isn't fair."That's a real concern, and we've got to think about both education and maybe a different kind of enforcement to get people to stop throwing their trash on the tracks because talk about something that's going to come back and bite you," said the mayor."I'm living this particular life now," he added. "But from 1979 to 1999 I did not own a car and almost exclusively got around by subway. It would have been in those years inconceivable not to be able to eat on the subway just because of life, because we're all incredibly busy in this city."Lhota called the mayor's comments "incendiary" and said enforcing littering laws in the subway is the NYPD's responsibility."It would be very, very helpful if they would enforce the laws," he said in an interview with the New York Post. "People throwing food and garbage on the tracks is a violation."The two men have a history as political opponents. Lhota, a Republican, ran for mayor but Democrat de Blasio won in 2013.The back and forth shifted to funding. The mayor critiqued Gov. Andrew Cuomo, saying people on trains aren't interested in money that's been recently spent on lighting up MTA bridges, instead saying they just want to get to work on time.Officials say grimy trash gets caught on the tracks, which can trigger track fires. The one on Monday injured nine people and left scores of others overheated, all while snarling the commute and leaving stations overcrowded and steamy.Lhota insisted that track cleanup campaigns will continue and expand."And new equipment in the form of portable vacuums and train-based vacuums that will run through the system through the night," he said.