The number of places with unhealthy Air Pollutant Index (API) readings has increased to 17 this afternoon from only six earlier.

The number of affected states also increased from four to five this afternoon.

According to the Department of Environment website, so far the highest API reading was recorded in Samarahan (184), Sri Aman (177) and Kuching (164) in Sarawak and Nilai (135) in Negri Sembilan.

Tanjung Malim, Perak, recorded the most drastic increase in reading, from good (31) to unhealthy (125).

Other areas which showed an increase in reading are Malacca City (86 to 103), Bukit Rambai (93 to 114) in Malacca; Port Dickson (81 to 105), Seremban (98 to 123) in Negri Sembilan; Banting (82 to 110), Port Klang (81 to 107), Petaling Jaya (84 to 110), Shah Alam (80 to 107) in Selangor; Batu Muda (92 to 114) in Kuala Lumpur; and Putrajaya (80 to 103).

Meanwhile, 29 other locations recorded a moderate API reading, while only six had a good API reading.

An API reading of 0-50 is categorised as good, 51-100 (moderate), 101-200 (unhealthy), 201-300 (very unhealthy), and 300 and above (hazardous).

The public can access updates through http://apims.doe.gov.my .

Meanwhile, the Meteorological Department said in a statement in Kuala Lumpur that haze-induced low visibility of less than five kilometres over the Straits of Malacca and Reef South is dangerous to vessels that do not have navigational equipment.

The condition, expected to persist till Monday (Sept 14) is also occurring over the waters off Kedah, Peneng, Perak, Selangor, Negri Sembilan, Malacca, Johor, Pahang, Sarawak, Labuan and Sabah.

The department also warned of strong winds and rough seas off Condore, Reef North, Layang-layang and Palawan from Monday (Sept 14).

The strong south-westerly winds of 40-50kph with waves up to 3.5 metres are expected to continue till Thursday (Sept 17).

This condition of strong winds and rough seas is dangerous to small vessels, sea recreational and sports activities.

- Bernama