After more than three decades, China has ended its one-child policy, the state-run Xinhua news agency reports.

The Chinese couples will now be allowed to have two children, it said, citing a statement from the Communist Party.

The controversial policy was introduced nationally in 1979, to slow the population growth rate.

It is estimated to have prevented about 400 million births. However, concerns at China’s ageing population led to pressure for change.

Couples who violated the one-child policy faced a variety of punishments, from fines and the loss of employment to forced abortions.

Over time, the policy has been relaxed in some provinces, as demographers and sociologists raised concerns about rising social costs and falling worker numbers.

The Communist Party began formally relaxing national rules two years ago, allowing couples in which at least one of the pair is an only child to have a second child.

In rural areas, families were allowed to have two children if the first was a girl.

Other exceptions included ethnic minorities and – since 2013 – couples where at least one was a single child.

Campaigners say the policy led to forced abortions, female infanticide, and the under-reporting of female births.

The decision to allow families to have two children was designed “to improve the balanced development of population” and to deal with an aging population, according to the statement from the Community Party’s Central Committee carried by the official Xinhua News Agency on October 29.

Currently about 30% of China’s population is over the age of 50.

Correspondents say that despite the relaxation of the rules, many couples may opt to only have one child, as one-child families have become the social norm.

The announcement comes on the final day of a summit of the Chinese Communist Party’s policy-making Central Committee, known as the fifth plenum.

The Chinese Communist Party is also set to announce growth targets and its next five year plan.