It can be noticed that China's population was very young.
Step-by-step explanation:
In this population pyramid of 1970 about China, it can be noticed the age distribution is much different than nowadays. While in the present China is facing problems because of aging population, in the 1970's it had problem because it had too much young population.
During this period, China's birthrates were very high, and the average lifespan was not really long per say, but nevertheless the population was exponentially growing. Out of fear of this trend, as the population was already huge, the Chinese government implemented laws that forbid the people to have more than one child, except in some cases.