What is the reason for increased sensitivity to allergens in children living in metro cities of India?

Step-by-step solution

The exaggerated response of the immune system to certain antigens present in the environment is called allergy. The substances to which such an immune response is produced are called allergens. The symptoms of allergic reactions include sneezing, watery eyes, running nose and difficulty in breathing This could be because of the protected environment provided early in life. The immune system is designed to recognize and respond to foreign antigens, not to attack self-cells. Higher vertebrates can distinguish foreign