1. Problem Understanding
Estimate daily takeoffs (departures) from Indira Gandhi International (IGI) Airport, Delhi.
We’ll use a passenger-throughput → flights approach (clean and commonly used).
2. Approach Summary
Annual passengers → passengers per day → average passengers per flight → total flights (arrivals + departures) → takeoffs ≈ half of movements
3. Step-by-Step Solution
Step 1: Start with annual passenger traffic (IGI)
Use a round, interview-friendly number for a major hub like Delhi: ~70 million passengers per year (this is in the right range for a big international hub).
Step 2: Convert to passengers per day
70M ÷ 365 ≈ ~190,000 passengers per day (this counts both arrivals + departures).
Step 3: Assume average passengers per aircraft
Mix of narrow-body and wide-body; reasonable blended average ≈ 140–160 passengers per flight.
Take midpoint: ~150 passengers/flight.
Total daily flight movements (arrivals + departures) ≈
190,000 ÷ 150 ≈ ~1,270 movements/day
(Each movement = one landing or one takeoff.)
Step 4: Derive takeoffs (departures)
Roughly half of movements are departures:
Takeoffs ≈ 1,270 ÷ 2 ≈ ~635 takeoffs per day
Step 5: Add buffers for cargo, positioning flights, and peak variation
Account for overnight freighters, repositioning flights, and day-to-day variation → add ~10–15%.
Buffered estimate: ~700–730 takeoffs/day
4. Final Answer
Delhi (IGI) has approximately 600–750 takeoffs per day.
A clean interview-ready figure: ~650–700 daily departures.
5. Interviewer-Ready Summary
- Annual passengers (IGI) ≈ 70M → ~190k/day
- Avg passengers/flight ≈ ~150 → ~1,270 movements/day
- Takeoffs ≈ half → ~635/day
- Add buffer (cargo/variation) → ~650–700 takeoffs/day