Fall in day and night temperatures due to early onset of the monsoon and critically high mosquito breeding indices being recorded in several areas across the Capital have once again given rise to fears of a dengue outbreak looming large over Delhi. In the light of this development, the Municipal Corporation of Delhi on Tuesday said it is initiating a series of measures to prevent vector-borne diseases. High breeding index A mosquito breeding index above 10 per cent is considered critical and it warns of an impending dengue outbreak. The National Vector Borne Disease Control Programme and the Municipal Corporation of Delhi teams have recorded dangerously high breeding indices at Model Town