Delhi administration has undertaken massive fogging and cleanliness drives to check the breeding of dengue mosquitoes in the capital. The three municipal corporations are also conducting awareness campaigns among the people in all the 272 wards. The civic authorities are also ensuring that no stagnant waters are stored near the human habitations.AIR Correspondent reports that as many as 685 cases of dengue have been so far reported in the city with 33 patients test positive yesterday.