Bangkok Tightens Black Smoke Standards Before PM2.5 Peak

BANGKOK, Nov 4 (TNA) - Bangkok has escalated its fight against air pollution by lowering the vehicle exhaust opacity limit from 30% to a strict 20%, effective November 1, as the city enters its peak PM2.5 season. 

Governor Chadchart Sittipunt announced the measure, which is part of a plan to curb emissions primarily from older diesel vehicles. The new standard aims to improve air quality by an estimated 24%, with the Governor also pushing the government to cut the repair grace period for vehicles failing the inspection from 30 days to just three days.

The Bangkok Metropolitan Administration (BMA) is shifting its enforcement strategy away from roadside checkpoints to pollution sources, including bus depots and construction sites, where all entering vehicles must now be on a "Green List" of compliant motors. 

Additionally, the BMA has expanded its ban on heavy trucks (over six wheels) that are not registered on the Green List during high-pollution days to cover all 50 districts.

To encourage private vehicle compliance, the "Green List Plus" program offers discounts for engine oil and filter changes, a simple maintenance practice found to reduce PM2.5 emissions by up to 42%. 

The Governor acknowledged that while vehicle exhaust is a primary source of pollution, he needs greater authority to inspect public transport vehicles and urged neighbouring provinces to curb crop burning, noting the pollution peak is expected in January 2026. -819 (TNA)