The Pollution Control Department has named the cleanest beaches for swimming, and the most polluted, in Thailand.
The department's Preeyaporn Suwanaged said on Tuesday the "best and worst" list came from a seawater-quality survey at 210 locations along coasts nationwide this year.
The survey found that the seawater at 49% of the locations was of good quality, 43% of moderate quality, 6% of deteriorated quality, and 2% highly deteriorated quality, she said.
The 10 with the cleanest seawater were all in the South, and most were in Krabi province.
Seawater of the best quality was at Samila beach in Songkhla province, followed by Nai Harn beach in Phuket, Ton Sai beach in Krabi, Maya beach in Krabi, Lo Samah bay in Krabi, Koh Yung in Krabi, Koh Kai in Krabi, Thai Mueang beach in Phangnga, Bang Ben beach in Ranong and Ban Thung Rin beach in Satun.
The department also listed the top five locations with highly polluted seawater. Many were in Samut Prakan province.
The most polluted seawater was found in the estuary of the Chao Phraya River in Samut Prakan, followed by the sea near bleach and dye factories in Samut Prakan, the 12 Thanwa canal estuary in Samut Prakan, Laem Chabang in Chon Buri and the estuary of the Tha Chin River in Samut Sakhon.
Ms Preeyaporn said that over the past decade, seawater along 90% of Thai coasts was of moderate to high quality. Significantly cleaner seawater was found along the Andaman Sea coast, and the most polluted in the inner Gulf of Thailand.
The discharge of nutrients and bacteria into the sea was the most common factor causing pollution, she said.