Twenty people were hospitalised today following a chlorine gas leak from an effluent treatment plant in Pimpri Chinchwad area in Pune district of Maharashtra.The leakage in the plant triggered a scare in the area with people living in nearby localities shifted temporarily as a precautionary measure. The patients, who complained of cough and eye irritation after the gas leak, are stated to be in a stable condition. The leakage has been plugged.