The 1990s have been the start of the decentralization, most notably by the upgrade of the Tambon Councils to Tambon Administrative Organizations, the upgrade of the sanitary districts to municipalities and also changes in the Provincial Administrative Organizations, all now elected local government bodies. Therefore these changes are also a minor topic of the point, though the most detailed on it is only found in footnote one of chapter three. I am quoting it completely:
Sadly, the two references which are quoted then are in Japanese only, so even less accessible than Thai source. The provincial governments mentioned are the PAO, which had overlapping responsibilities with the TAO and therefore needed a thorough revision.
In the early 1990s, both the budget and the number of local government employees accounted for less than 10% of those of the national government. Interior Ministry officials, including the provincial governors, played the key roles in this centralized system of local administration. One of the main aims of the decentralization campaign was to replace provincial governors appointed by the Interior Ministry with popularly elected local government heads. However, the provincial governor's offices were very important within the Interior Ministry bureaucracy, being equal in rank and prestige to the ministry director's post. Thus for many Interior Ministry officials, such an appointment is the highlight of their career. It was only natural, therefore, that the ministry should stubbornly resist. Furthermore, decentralization was not only a problem for the Interior Ministry, but would affect almost all of the ministries and departments of the central government. Although some ministries actually welcomes the prospect of less supervision by the Interior Ministry officials, they attempted to protect themselves from the waves of decentralization by delegating authority to local agencies (deconcentration). Many party politicians were not very enthusiastic about decentralization, either. One reason was that they had long relied upon the cooperation of bureaucrats in elections. More importantly, though, decentralization would reduce the powers of ministers, and thus the vested interests of party politicians. As a result, a compromised form of decentralization was agreed upon in 1994 that was to upgrade about 7000 small administrative wards (tambon) throughout the country to municipal government status. The Tambon Council and Tambon Administrative Authority Law came into force on 1 March 1995. Further decentralization occurred thereafter. Prior to these changes, rural areas other than cities and sanitary districts had been governed by the province as local administrative units. Since rural areas came under the governance of tambon administrative authorities, the provincial governments were reorganized (on 1 November 1997) to preserve themselves. Also, based on the provisions concerning decentralization in the 1997 Constitution, there was a wholesale revision of related laws and regulations on local government.