New Delhi: Stricter radiation emission norms for mobile towers came into effect from on Saturday, with a view to reduce emission to one-tenth of the present levels. Failure to stick to the prescribed levels will attract a penalty of Rs 5 lakh per tower. Radiation norms for mobile handsets have been made more stringent, but cell-phone makers have been given a year to comply with new guidelines. Telecom Minister Kapil Sibal had said the new limits for towers were 10 times more stringent than norms followed in most parts of the world. (PTI)