According to the most recent World Health Organization data, there are some good reasons to be worried about the air quality in Lahore, with an yearly average of 68 µg/m3 of PM2.5, which corresponds to a 155 - Unhealthy Air Quality Index
Obviously, 165 - Unhealthy is just a yearly average, and the air pollution can reach much higher 300+ hazardous levels- just like the recent smog events in early November 2016.
Unfortunately, there is currently no known Air Quality monitoring network with PM2.5 data available in Lahore, nor in Pakistan (source).
Air quality is considered satisfactory, and air pollution poses little or no risk
None
51 -100
Moderate
Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.
Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion.
101-150
Unhealthy for Sensitive Groups
Members of sensitive groups may experience health effects. The general public is not likely to be affected.
Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion.
151-200
Unhealthy
Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects
Active children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion; everyone else, especially children, should limit prolonged outdoor exertion
201-300
Very Unhealthy
Health warnings of emergency conditions. The entire population is more likely to be affected.
Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion.
300+
Hazardous
Health alert: everyone may experience more serious health effects
For very useful health advices of Beijing Doctor Richard Saint Cyr MD, check www.myhealthbeijing.com blog.
Usage Notice: All the Air Quality data are unvalidated at the time of publication, and due to quality assurance these data may be amended, without notice, at any time. The World Air Quality Index project has exercised all reasonable skill and care in compiling the contents of this information and under no circumstances will the World Air Quality Index project team or its agents be liable in contract, tort or otherwise for any loss, injury or damage arising directly or indirectly from the supply of this data.