Authorities in Yunnan province will construct or renovate more than 600 toilets at major scenic spots in the next three years in an effort to bolster tourism, the Yunnan Provincial Commission of Tourism Development said in a draft plan released on Tuesday.

Tourism is one of the pillar industries for the province in Southwest China, which recorded a total of 285 million trips by domestic and foreign tourists last year. According to the commission, the tourism industry generated total revenue of 265 billion yuan ($42.3 billion) in 2014, accounting for more than 20 percent of the province's GDP.

However, the number of foreign tourists has dropped for at least five years in a row, decreasing by 0.46 percent last year, Yunnan Daily reported.

"The sites for many toilets on some tourist routes were inappropriate ... and a large number of toilets were poorly maintained and have long been the subject of complaints from tourists," it said.

The campaign is part of China's three-year "toilet revolution" aimed at building a total of 33,000 restrooms and renovating 24,000 by 2017, said Li Jinzao, head of the China National Tourism Administration. This year, 13,000 new toilets will be built and another 9,000 renovated across the country.