Two children have so far succumbed to dengue ever since the disease began spreading in the capital early this month.
Thirty cases were reported from three municipal corporations while two were from the VVIP areas of the capital.
One case originated from outside the capital.
South Delhi Municipal Corporation reported the maximum number of cases at 256, while 227 cases were detected from the North Delhi Municipal Corporation area and 171 cases have so far been reported from East Delhi Municipal Corporation.
Other cases were reported from NDMC and Delhi cantonment areas.
Out of the 685 cases, seven cases have been reported from outside Delhi.
The capital saw 548 cases of dengue, including eight originating from outside, and four deaths last year while the year before reported 4,903 cases, including 26 from outside, and eight deaths.
In 2009, there were 172 dengue cases and no deaths while in 2008, there were 995 dengue cases and two deaths.