HomeUPSCThe equal length of day and night on September 23rd in all parts of the world is known as – 383. The equal length of day and night on September 23rd in all parts of the world is known as –By Admin / October 4, 2025 A. Autumnal Equinox B. Celestial Equinox C. Winter Equinox D. Vernal Equinox ✅ The correct answer is option A.