Policeman Mandar Divse, a triple gold medallist last year, sizzled the pool with a new meet record as he won the men's 1500m freestyle, while Taniya Ganguly bettered her own national record in the three-metre springboard diving in the 58th Senior National Aquatics Championships in Delhi on Thursday.

Four new records fell during the day, with Karnataka and Police bagging seven medals each on the third day of the meet at Dr Shyama Prasad Mookerji swimming pool.

The other record breakers were Police's T K Senthil Kumar (men's 200m backstroke) and Arjun Muralidharan (men's 100m butterfly).

In diving, Taniya bettered her own national record, tallying 389.50 points.

Mandar, who turned in a lacklustre performance in the 400m freestyle on the opening day, clocked 16 minutes, 33.60 seconds to better the four-year-old record of 16:48.82, set by Kailash Nath of Police.

Though this was not Mandar's best timing, the Maharashtra swimmer was happy with the effort.

"I had given some real bad timings after the SAF Games. So I'm happy with today's performance," said Mandar, who finished at least 50m ahead of second-placed Rohith Hawaldar of Karnataka (17:10.89).

Mandar's personal best came in the SAF Games in Islamabad in March, where he clocked 16:30.83.

In 200 backstroke, Senthil clocked 2:11.97 seconds to finish ahead of Akbar Ali Mir of Railways, last year's gold medallist in the event. Mir clocked 2:13.56.

Muralidharan won the 100 butterfly in 56.29 seconds, erasing Railways' K Suresh's decade old record of 57.79 seconds.

Charu Mishra of Police won the 800m freestyle, covering the distance in 9 minutes, 49.23 seconds.

In the women's 100 butterfly, Richa Mishra of Police won the gold medal.

Olympian Shikha Tandon had another good day as she won her third consecutive gold. After winning the 4 x 200m relay and 50m freestyle the previous days, Shikha produced her personal best timing of 2:29.85 seconds to win the 200m backstroke.