Mobile towers in Mumbai safe Daily News & Analysis The Cellular Operators' Association of India (COAI) on Wednesday said the exposure limit of radiation due to mobile phone towers in Mumbai is safely below permissible limits as per international standards. Even as the telecom ministry has adopted an exposure limit of 9.2 watts/sq m as 'safe', countries like Switzerland and Italy have exposure limits as low as 0.095 watts/sq m. "The department of telecom is considering reducing current exposure limits by less than 1/10th the current limit up to 0.45 watts per square metre by September this year," said Rajan Mathews, Director General, COAI.