OnUber Lyft Ride Sharee argument in favor of TNCs such as Uber and Lyft is that they can take privately-owned cars off the road. But a new study says the vehicles actually generate more pollution than they replace.

The Union of Concerned Scientists, a nonprofit science advocacy organization focusing on environmental and social challenges, says they found TNC trips generated 69 percent more pollution than the trips they displace; those trips, the group says, are frequently transit, walking, or micro-mobility.

“For ride-hailing to contribute to better climate and congestion outcomes, trips must be pooled and electric, displace single-occupancy car trips more often, and encourage low-emissions modes such as mass transit, biking, and walking,” the group says.

Lyft called the report “misleading” and said they encourage shared rides and deploying electric vehicles. Read the whole story here.