Dangerous smoke from raging forest fires in Laos, Myanmar, and Thailand has created a public health crisis across the Mekong region. Firefighters are struggling to combat the blazes in parched conditions.

Forest fires raging through Laos, Myanmar and Thailand have smothered large areas in dangerous smoke, leaving overstretched firefighters battling blazes and smog-choked communities looking to the skies for rain and their governments to fix a scourge that worsens each year. Dry season fires have brought a public health crisis to northern Thailand, including Chiang Mai, as well as much of Laos and eastern Myanmar, as parched bush provides tinderbox conditions for wildfires. Some fires are also due...