Air movement in any space is one of the main factors of Human thermal comfort for the occupants. It is also related with the type of activity in that space, clothing the occupants are wearing and the ambient air temperature that particular space has. Wales Millennium Centre (main Theatre) is designed for multiple performances-based activities. In the recent years, it has been observed that when the main curtain of a stage is lifted, there is always a huge down draught of air coming towards the front rows of seating area, making it uncomfortable for the spectators sitting there. In this paper, multiple Computational Fluid Dynamic (CFD) simulations are performed using Win Air4 software. The research found that most of the time the ventilation system was working well but noticed a higher temperature at the back-seating area of the hall. The paper suggests appropriate locations of inlets and outlets which should have been given to address this issue. The paper presents some viable solutions for the uncomfortable conditions that can be improved by providing more supply of air at the backseating area and extract points at the top of the main ceiling, by providing cooling fins under the ceilings and keeping the stage air supply off as per the results of simulations discussed.