| Item | Value used | Source / industry standard |
|---|---|---|
| Flight distance basis | Great-circle (haversine) + 95 km correction | ICAO uses great-circle distance to estimate fuel burn; +95 km uplift per UK DEFRA/BEIS for routing, holding & taxi |
| Air emission factor | 0.246 kg CO₂e / passenger-km | DEFRA / GHG-Protocol domestic-flight factor (average passenger, incl. radiative forcing) |
| Cab (ground) emission factor | 0.171 kg CO₂ / km (diesel sedan) | India range 0.13–0.20 kg/km — WRI India-specific road-transport factors / typical medium diesel car |
| Traveller cab trips | 2 (home: centre↔airport) + 2 (destination: airport↔centre), per traveller | Each traveller assumed to take own diesel cab both ends |
| Local resident cab | 1 round trip = 2 × local distance, per resident | People already in the host city skip flights/airport; BLR/HYD/BOM/VNS 15 km, DEL 20 km one way |
| Flight directionality | Round trip per traveller (there & back) | |
| Headcount | Editable per city (default 1) | Your input; optimum is weighted by these |
| Airport↔centre distance | BLR 35 · DEL 16 · HYD 30 · BOM 20 · VNS 26 km | City defaults, one way |
| Optimum rule | min Σ (people × their travel: flight + cabs, or local cab if resident) | Lowest total CO₂e across the candidate cities |
Sources: ICAO Carbon Emissions Calculator (ICEC) · ICEC Methodology v13.1 · UK DEFRA/BEIS Greenhouse-gas conversion factors (flights) · WRI India-Specific Road Transport Emission Factors (2015). Figures are estimates for comparison, not billing-grade.
Air — distance. Great-circle distance (haversine) between airport coordinates — ICAO's basis — plus the standard +95 km correction (DEFRA) for indirect routing, holding and taxiing.
Air — emissions. Distance × 0.246 kg CO₂e per passenger-km (DEFRA/GHG-Protocol domestic factor, average passenger, incl. radiative forcing).
Ground — cab. Diesel sedan in Indian conditions at 0.171 kg CO₂/km. Travellers: home centre→airport→centre + destination airport→centre→airport. Residents of the host city: one local round trip (2 × local distance) only.
Airports: BLR Kempegowda, DEL Indira Gandhi, HYD Rajiv Gandhi, BOM Chhatrapati Shivaji Maharaj, VNS Lal Bahadur Shastri (Varanasi). Round-trip flight per traveller. Estimates for comparison, not billing-grade.