Air pollutant index (API) readings in Seremban are recorded at 61, a moderate reading as compared to 78 the previous day. Pix by Hazreen Mohamad

SEREMBAN: The air quality showed a slight improvement at three monitoring stations in Negri Sembilan compared to Wednesday.

At 2pm today, the air pollutant index (API) readings in Seremban are recorded at 61, Nilai (75) and Port Dickson (66).

At 3pm yesterday, the API is Seremban was at 78, Nilai (79) and Port Dickson (72).

The air pollution level is categorised as — good (zero to 50), moderate (51-100), unhealthy (101 to 200), very unhealthy (201-300) and hazardous (301 and more).

It is believed that the perennial haze returned to Malaysia due to open burning fires in Indonesia. As of Tuesday, the satellites have detected 152 hot spots in Sumatra and 74 in Kalimantan.