In the metropolitan cities of $India$,many children are suffering from allergy/asthma. What are the main causes of this problem? Give some symptoms of allergic reactions.

(N/A) Allergy is the exaggerated response of the immune system to certain antigens present in the environment.
In metropolitan cities,the lifestyle is responsible for the lowering of immunity and increased sensitivity to allergens. The highly polluted environment of metro cities significantly increases the chances of allergy and asthma in children.
Some common symptoms of allergic reactions include sneezing,watery eyes,running nose,and difficulty in breathing.