A wave of thick toxic smog has blanketed Pakistan's second largest city of Lahore, causing tens of thousands of people to fall ill. Doctors have advised residents to take shelter.

Health officials estimate that there has been at least a 50% rise in pediatric patients since November. Poor air quality has exacerbated respiratory issues.

A hospital says that smog is affecting many children, particularly those at school age.

Residents say air pollution is a regular problem that severely affects their health and daily activities. Many are calling on the government to do something about the situation.

Experts believe the burning of crops for the winter wheat-planting season is a major cause.

Last month, the local government in Lahore ordered offices and markets to remain closed on weekends in an attempt to help cut toxic levels of smog.