Haemoglobin is the red protein pigment, which carries oxygen in the blood. In anaemia, the amount of haemoglobin is decreased thus impairing the amount of oxygen delivered to tissues. A patient of anaemia may complain of fatigue, weakness, breathlessness, chest pain, etc. At high altitudes, the amount of oxygen present in the air is less and the oxygen level is quite low at an altitude of 2,500 metres and above. This can pose problems for people who normally reside at lower altitudes because their bodies aren't used to working on so little oxygen. The body begins to adapt to the lowered oxygen level when we travel to high altitude but this adjustment takes several days. A healthy person can probably safely go from sea level to an altitude of 2,500 metres in a few days but beyond this, the ascent should not be more than 300 metres a day. The problem is compounded in the presence of anaemia. Your wife may feel sick and suffer from breathlessness, headache, etc. if she will to go to Leh. It is probably best that she does not travel. Please have her investigated to find the cause of anaemia so that appropriate treatment can be given.