The total number of dengue cases have also risen to 180 while the chikungunya cases stand at 220 till July 29, it said.
The season for the vector-borne diseases kicked in mid-July and it generally lasts till November-end.
Cases of all the three vector-borne diseases were reported much earlier this time, which doctors had attributed to early arrival of monsoon.
Of the 288 malaria cases, 137 affected people were residents of Delhi while the rest of the cases diagnosed in New Delhi were traced to other states. At least 79 cases have been recorded this month.
Of the 220 chikungunya cases, 140 of the affected people were residents of Delhi while the rest of the cases were from other states, it said.
Dengue and chikungunya are caused by the aedes agypti mosquito, which breeds in clear water. The anopheles mosquito, which causes malaria, can breed in both fresh and muddy water. Breeding of mosquitoes has been reported at 80,411 households in Delhi, according to the report.
All the three municipal corporations have stepped up awareness drives -- distributing pamphlets and plying vehicles with loudspeakers issuing dos and don'ts on prevention of the diseases.
The Delhi government had on June 23 issued instructions to state-run and private hospitals and nursing homes to increase their bed capacity by up to 20 per cent for the next six months to deal with a possible outbreak of dengue and chikungunya.