Population rise is an unavoidable evil.

Explanation

The natural resources like air, land and water on the earth are in limited amount. Against it the level of human population rises very fast. Industralization and urbanization take place due to population rise. That increases pressure on these natural resources.
The social problems like poverty, malnutrition, anarchy increase. The most part of population remain deprived of basic necessesities of life like food, shelter and clothes. Thus population rise is an unavoidable evil.