New Delhi, Feb. 17 -- As cities worldwide tighten restrictions on diesel emissions, a lesser-known form of air pollution is growing unchecked-brake dust. While exhaust fumes have long been recognised as a health hazard, new research suggests that the microscopic particles released when vehicles brake, may be even more harmful to human lungs. With the rise of heavier electric vehicles, which lead to increased brake wear, the urgency to address this issue has never been greater.

Every time a vehicle slows down, friction between brake pads and discs produces tiny airborne particles. These particles, known as brake dust, make up a significant portion-up to 55%-of all traffic-related fine particles in urban areas.

Unlike exhaust emissions, b...