Mood: The mood of the video appears to be melancholic and introspective, with a sense of longing. The theme seems to revolve around heartbreak, loss, or separation, as hinted by the title 'Jab Tu Saath Nahi Hota' which translates to 'When You Are Not By My Side'. The overall emotion conveyed is one of yearning and nostalgia.

Environment: The setting of the video seems to be a dimly lit stage or performance area, with the artist singing into a microphone. The background is blurred, but it appears to be a live performance or a music video shoot. The dark background with red and blue lights creates an intimate and emotive atmosphere.