Subway cars are dirtier, for the first time in five years, according to a study released yesterday by an advocacy group for subway riders. The group, the Straphangers Campaign, attributes the decline in cleanliness to reductions in the number of transit workers who clean the cars.

Cars on eight subway lines were judged by members of the Straphangers Campaign to be significantly dirtier than they were last year. At the top of the list were the nos. 1/9, 3, 5, and 6, and the B, E, M, and V lines. The seventh annual survey rated only 14% of cars as clean on the 1/9 line, while on the best line, the N, 86% of cars were rated clean.

The survey used a rating system similar to one employed by New York City Transit inspectors to rate car cleanliness. While results of the two surveys differ, both the Straphangers and the New York City Transit surveys showed cleanliness has declined since 2003.

A spokesman for New York City Transit, Charles Seaton, said the Straphangers’ survey rates cars in the middle of their routes, whereas the transit agency’s surveyors rate cars at the terminal after they’ve been cleaned.

“We have no control of the cleanliness of a car in the middle of a run,” Mr. Seaton said. He added that cars rated as the dirtiest by the Straphangers’ survey, the 1/9, travel twice as long without being cleaned, because there is no cleaning station at the South Ferry terminal.

In its Passenger Environment Survey, New York City Transit found a slight deterioration in subway car cleanliness during the second half of last year, the same time the Straphangers’ survey was conducted. The percentage of cars that were rated clean declined from 83% to 81%.

In 2003, the Metropolitan Transportation Authority, parent of New York City Transit, began not to fill vacancies in subway-car cleaners’ positions, as part of an effort to close a budget gap. Transit officials justified the move by saying they had achieved a more efficient way to clean the system. According to the MTA’s 2005 budget, New York City Transit adopted a “cleaner deployment saving” program that saved $8.9 million in 2003 and $8.4 million in 2004. In 2005, the transit agency plans to save $2.5 million by not filling vacancies created by the retirement of subway-car cleaners.

“We thought the cuts would catch up with them,” the campaign coordinator for the Straphangers Campaign, Neysa Pranger, said. “There is only so much efficiency you can achieve through better management. What they need is more people on the ground doing the cleaning.Those positions haven’t been filled, and the subways have gotten dirtier as a result.”

New York City Transit attributed the decrease in cleanliness to a surge in ridership, which reached a record 1.4 billion riders last year.

Cleanliness – hardly a concept with a universal meaning – was defined in narrow terms for the Straphangers survey. Open trash, rolling bottles, and bad smells were included in cars rated dirty. The survey, though, was essentially a measure of “grime, not dirt,” which indicates how well workers cleaned subway cars. It was not a measure of how dirty subway riders are.

Recent subway fires caused by debris on the tracks, as well as other major service disruptions, have raised concerns that the subway system has begun to deteriorate as a result of cost cutting efforts. Ms. Pranger said she believed the authority has spent enough money to bring the system into a state of good repair, but she said recent cuts would surely result in deterioration of service. Referring to the effects such cuts have had on subway cars, she added: “This is what you get,” she said.