Short answer
Rest completely for your first 24 hours in Leh at 3,500 m and stay two full nights before going higher. After that, never sleep more than 500 m above the previous night. Drink 3 to 4 litres of water daily, avoid alcohol for 48 hours, and discuss Diamox with your doctor before you travel.
Flying into Leh takes 80 minutes from Delhi and drops you into air holding about 65% of the oxygen you had at breakfast. Studies at Leh have found acute mountain sickness in a quarter to a third of arrivals by air, against a small fraction of those who drove up from Manali or Srinagar over three days.
Fitness gives no protection. The only variables that reliably matter are how quickly you ascended and how high you sleep. Climb high and sleep low: driving to Khardung La at 5,359 m and returning to Leh to sleep is fine, but sleeping at Pangong at 4,250 m on day three is not.
Symptoms to act on are a headache plus nausea, dizziness or unusual fatigue. Stop, rest, hydrate and take paracetamol. Descend immediately for confusion, breathlessness while sitting still, a wet cough, or an inability to walk heel-to-toe in a straight line — these signal cerebral or pulmonary oedema.
| Night | Base | Altitude | Activity |
|---|---|---|---|
| 1–2 | Leh | 3,500 m | Rest day one entirely; gentle monastery drives on day two |
| 3–4 | Nubra (Hunder) | 3,050 m | Cross Khardung La at 5,359 m, sleep lower than Leh |
| 5–6 | Pangong Tso | 4,250 m | Only after five nights of adaptation |
| 7 | Leh | 3,500 m | Descend and rest before the morning flight out |