BEIJING, Dec. 30 -- China will ensure risks are controllable and major fluctuations in fertility levels are prevented while loosening the one-child policy, according to a guideline on Monday.

The guideline, issued by the Communist Party of China(CPC) Central Committee and the State Council, China's cabinet, stressed improved population quality, balanced demographic structure and a population policy that coordinates population growth with economic development, the environment and natural resources.

Provincial-level administrations will formulate their own implementation plan based on local demographics.

Top Party and government leaders will take charge of implementation, according to the guideline, and authorities should tackle gender imbalances and strictly control violations of the policy.

China's family planning policy was introduced in the late 1970s to control the population by limiting most urban couples to one child and most rural couples to two children, if the first child was a girl. It is estimated that the policy has prevented some 400 million births.

In November, the CPC approved a key decision which allows couples to have two children if one of them is an only child.

Last week, the bimonthly session of the Standing Committee of the National People's Congress, the top legislature, passed a resolution on family planning, entrusting provincial congresses and their standing committees to make their own calls on implementation.

The new policy does not change the basic state policy of family planning. The guideline says family planning "conforms to the requirements for the country's long-term development and the fundamental interests of the people".