New York City’s new congestion pricing plan was supposed to make traffic better and air cleaner. But for residents in the South Bronx, it might be doing the opposite. Early numbers from the first few weeks of the tolling system show a possible increase in traffic in the neighborhood, raising concerns about worsening air quality.

The South Bronx already struggles with high pollution levels, thanks to the heavy truck traffic on the Cross Bronx Expressway. Asthma rates here are some of the highest in the city, and locals worry that if drivers start avoiding Manhattan tolls by taking detours through the Bronx, things could get even worse.

“You want to reduce congestion? Please do it here, where we’re breathing toxic air,” said Mychal Johnson, co-founder of South Bronx Unite, a group focused on environmental and social issues.

It’s still early to say for sure, but data from Inrix, a company that analyzes traffic, shows a 9% increase in afternoon travel times on major Bronx highways during the first two weeks of congestion pricing compared to the same period last year. Morning travel times, however, dropped by 2%. Longer travel times can mean more traffic, though they can also be caused by accidents or construction.

The Bronx has long been a hotspot for pollution, and this new tolling plan might be adding fuel to the fire. For now, activists and residents are keeping a close eye on the situation, hoping the city will address their concerns before the air gets harder to breathe.