The rural to urban migration is not a boon to a country. In the long run, it even affects our ecosystem. The use of terrain becomes highly imbalanced. Certain urban regions become terribly hot and deforested. The climate around the urban regions changes over a few decades. This is what happened in Hyderabad or other major cities that have developed recently - as an example.
The rural areas have become dilute in population. The education, jobs, center of action, people's preference etc. have become concentrated in the urban regions. The rural areas are neglected and they suffer lack of advanced medical facilities and there are less number of powerful persons in that region.