This Earth Day, free T rides will not be an option as they have in previous years, due to “budgetary constraints,” according to MBTA spokeswoman Lydia Rivera.

“[The Massachusetts Bay Transportation Authority] had to begin to tighten its spending,” she said. She added that the free service, which was supposed to promote environmental awareness, has not been offered the past couple of years.

In January, the MBTA raised T fares from $1 to $1.25 to make up for a recent 5 percent drop in T ridership in the past year. The free service was offered three to four years ago, but Rivera said even one free day this year would mean “significant” losses.

T Rider’s Union Coordinator Khalida Smalls said the MBTA should look past budgetary constraints and offer the free rides.

“Why are they being so cheap?” she said. “It’s beginning to break with a healthy tradition and a positive tradition.”

Rivera said the MBTA supports Earth Day, but not being able to offer the free rides was “something beyond our control.”

Jim Gomes, the president of the Environmental League of Massachusetts, said he understands the MBTA’s financial concerns, but there is still a long way to go.

“[Taking the T is] a whole lot better than people in their cars by themselves,” he said. He also said he credits the MBTA for purchasing new lower-emission buses.

According to the MBTA website, they have purchased 600 “environmentally-friendly” buses to lower emissions and replace older diesel buses.

Rivera did not rule out the possibility that Earth Day could be a free day for T riders once again.

“You never can tell,” she said. “It may or may not.”