The Straphangers Campaign survey released Monday found that in 2009, only half of subway cars were clean, down from 57 percent a year earlier. The group's survey, called "Subway Shmutz," found the M line to be the dirtiest, and the No. 6 and C lines to be the cleanest.
"Eleven of the 22 subway lines, fully half, grew worse, while five lines improved and six lines stayed the same," the report said.
The campaign blamed budget cuts at the Metropolitan Transportation Authority for the decline. There were 43 fewer car-cleaners in 2009 than in 2008, and 108 more are slated to be cut in the 2010 budget.
"It's as clear as the grime on a subway car floor: MTA transit cuts in cleaners has meant dirtier cars," the group's spokesman, Gene Russianoff, wrote. "And more cuts to come means more dirt for subway riders."
The survey was based on 2,200 observations of subway floors and seats.
NYC Transit conducts its own subway cleanliness survey. Its findings showed improvement in overall cleanliness, with 95 percent of subway cars being clean for the second half of 2009.
The two surveys use similar, but not identical, methodology.