
The fog was especially thick on mountain roads, including the Lampang-Tak Road in Koh Kha, Somprab and Thoen districts and Lampang-Ngao-Phayao Road in Ngao disrict.
Motorists should drive slowly and use fog lights because of low visibility, said Chakorn Na-Lampang, chief of the Disaster Mitigation Office in Thoen district.
Accidents often occurred when there was thick fog, he said.