There are 4 waves of decentralization in Thailand. The second wave of decentralization was seen in 1950s, when several kinds local government were newly of introduced in Thailand.
One was sanitary districts(in Thai, called as Sukhaphibar). Sanitary districts were established in the semi-urban areas, economically prosperous areas next to Thesaban areas, and in the district office areas Sanitary districts, firstly established in 1953, showed remarkable increase of its number to 981 places until 1999. Another kind of local government was the Provincial Administrative organization(PAo). Its