Hello Mr Chakraborty,
Altitude of 1500 to 3500 m is definitely 'High Altitude'. Normal healthy, young people from the sea level find difficulty in breathing and working at such altitudes. You will really be risking your life, with your lung problems, if you were to go to high altitudes.
Is going to 3000 m an absolute must? Then travel by road, ascending very gradually and acclimatizing yourself to the altitude. Flying into an area at 3000 m is very unsafe with your medical background. You should have some experienced travelers accompanying you for help. Make prior arrangements to quickly bring you down to lower altitudes for medical help
, at the earliest symptom of any chest discomfort
, headache, nausea, vomiting
or muscle cramps
You have to quit smoking
and alcohol totally. Have plenty of fluids to drink, preferably fruit juices and soups.
Wishing you the best of health and happiness always