Talk to Pediatrician on Asthmatic, Bronchitis, Brochospasm

Asalam u Allaikum Respected Doctors, my son 11 yrs suffering from acute asthma and bronchitis , I have shown him to so many child specialist but nothing happens to my boy. In summer he apparently goes well but as winter starts he is starts with cough, chest whistle, and his nebulization starts. There is so much more to tell. Please suggest me a best pulmonoligist in Hyderabad.