China has been making significant progress in cleaning up its toilets, according to the National Tourism Administration, since the launch of a three-year "toilet revolution" which aims to build 33,000 restrooms and renovate 24,000 others by next year.

By the end of last year, 22,009 had been built or upgraded, 4 percent more than the target.

China will build or renovate 25,000 facilities this year, at a cost of more than 12.5 billion yuan (US$1.9 billion), the NTA said, and it will also work to improve toilets in rural areas.

Toilets in the countryside have earned a nasty reputation, with some little more than ramshackle shelters surrounded by cornstalks and others just open pits next to pigsties. The ongoing "toilet revolution" is set to change all that.

China's national standard requires "sanitary" toilets in rural homes to have walls, roofs, doors and windows and to be at least 2 square meters.

In the eastern province of Shandong, toilets in rural areas were often just roofless structures made of mud or rock.

"When children from the cities come to our village, they would rather hold it the whole time than use the pits," said Feng Jinghua, Party chief of Zhouzhuang Village in Qufu.

According to the Chinese Center for Disease Control and Prevention, 80 percent of infectious diseases in rural China are caused by fecal contamination and unsafe drinking water. More than 30 types of infectious diseases, including diarrhea and cholera, are linked to pollution from human waste.

So far, more than 8 million of Shandong's 15 million rural families have flush or dry toilets and the provincial government plans to earmark more than 10 billion yuan to help upgrade the toilets of some 6.5 million rural families by the end of 2018.

"In the past, when we went to fairs in the nearby town, we did not even know how to use the flush toilets there," said Zhang Ruiyi, a farmer in Wuliqiao Village in Jiyuan, a city in central China's Henan Province.

In Zhang's village, all 112 families now have flush toilets, while in Jiyuan, about 90 percent of rural areas have flush toilets.

In the eastern province of Jiangsu, 94 percent of rural homes have sanitary toilets, the highest rate in the country, according to Chen Xiaojin, deputy chief of the provincial health department.

According to official figures, 75 percent of rural homes in China had flush toilets or dry toilets by the end of 2015.

Beijing had gone through four "toilet revolutions" — in 1965, 1989, 1994 and 2002 — to eliminate pit toilets and fees for use as well as renovate public toilets in alleyways. As of 2015, there were almost six public toilets per 10,000 people in the city, compared to the national standard of four.

Another "toilet revolution" is planned for the capital over the next five years to improve sanitation and service levels.

Authorities aim to build 100 toilets with Wi-Fi access this year. The toilets, to be built in Tongzhou and Fangshan districts, will also have ATM machines and charging facilities for cellphones and electric vehicles, said Ji Yang, a city official.

Baby seats will be installed next to the toilets for the benefit of mothers.

The estimated cost of each toilet is between 50,000 and 100,000 yuan.

Urinals for children and barrier-free facilities will be installed in the city's current toilets, together with ventilation and air conditioning systems to ensure a stable temperature of at least 12 degrees Celsius in winter and 30 degrees Celsius in summer, he said.