The Ministry of Housing and Urban-Rural Development of China has released the new criteria for the design of public toilets on the eve of the fourth World Toilet Day, which falls on Saturday, raising the number of women’s washrooms.

The proportion of female and male stalls will increase from 1:1 to 3:2, according to the new rules. In crowded areas, female stalls may be twice as many as that for male.

The new criteria will become effective on Dec 1, 2016.

The theme of the World Toilet Day this year is "toilets and jobs", focusing on how sanitation, or the lack of it, can impact people’s livelihoods.

It has long been a problem in mainland cities that women have to wait in long lines to use toilets.

Shanghai has constructed 10 unisex stalls in a busy park in Pudong New Area this year in order to make it more convenient for residents, but not all people have embraced the idea and some have called for doubling female toilets to solve the problem.

The ministry said that the new ratio of women’s and men’s toilets is based on the results of a survey on 726,000 people it conducted earlier.

Chai Pingyan contributed to this story.