Jaipur, October 2 Traditional hookah and chillum are more injurious to health than cigarette, a study has said. The study underlines that the old mode of smoking is much more toxic than cigarette smoke as carbon monoxide (CO) level is higher in it, the study conducted by a group of pulmonary doctors of the SMS Hospital Medical College and the Asthma Bhawan here said. The study assumes significance in the wake of ongoing debates on the ill effects of smoking and the countrywide ban on lighting up the rolled tobacco at public places, which came into force today. Professor of medicine Virendra Singh, who was a part of the study claims that the traditional smoking ways can be fatal.