Daylight FactorIs the window big enough? Average daylight factor from room size, glass and what's outside, checked against the target for the room and the NBC window rule.

Obstruction angle: how high the building or trees opposite rise above the window centre, seen from the window. 0° = open sky. Targets: IS 2440 / SP 41 unless marked UK (BS 8206-2). Indian daylight factors are set for an 8,000 lux design sky, so 1.9% ≈ 150 lux.