When in Shangrile someone has breathing difficulty what should he or she do to overcome it ?

It is Mountain Sickness of the difficulty breathing. The following precautions may help to prevent or lessen the effects of the Mountain Sickness:
Since fluid loss usually accompanies the acclimatization process, drink plenty of fluids (3 - 4 litres daily at least) and eat carbohydrate food to keep the body properly hydrated;
Do not over exert and only partake in light activity immediate after your arrival;
Don't smoke, drink alcohol or take other depressants such as tranquilizers and sleeping pills. These will depress the respiratory drive and limit oxygen intake.