In Nuclear Power Plant (NPP), it is necessary to remove particulate matter and gaseous pollutants from gas stream before releasing into atmosphere during abnormal conditions such as severe accidents. There are many efforts have been made in past to remove pollutants. In view of environmental aspects and stringent regulation of nuclear safety, this paper presents experimental investigation on performance of venturi scrubber. The experimentation is carried out in submerged condition. The venturi scrubber has been designed, developed and fabricated for experimental analysis to study iodine removal efficiency in self-priming mode. The investigation consists of contamination of air by mixing iodine vapours using pressure cooker and suction venturi system. Contaminated air is used to evaluate performance of venturi scrubber. The water is used as scrubbing fluid. Iodine removal efficiency is considered as one of the important performance parameters of venturi and it is determined experimentally with variable pH of scrubbing fluid and iodine inlet concentration. Iodometric titration is used to find iodine amount in scrubbing fluid. It has been found that pH of water improves performance efficiency of venturi. It is observed that iodine is more soluble at higher values of pH and performance efficiency of venturi gets improved with increase in pH of water. Performance efficiency is also improved with an increase in iodine inlet concentration. The liquid to gas ratio (L/G ratio) is one of the important parameters of iodine removal efficiency of venturi scrubber. This has been also observed that liquid L/G ratio increases with increase in water column of primary tank due to increase in hydrostatic pressure of water column at throat of venturi scrubber.