The incident happened this morning around 4.30 AM, when the constables were patrolling in a PCR van heard cries of a woman from a drain near Geeta Colony flyover, he said.
"They saw the woman neck deep in the drain. They immediately took off their uniforms, tied it together into a rope and pulled out her," DCP (Conrtrol Room), R K Singh said.
She was rushed to Aruna Asaf Ali hospital in an unconscious state, he said.
The identity of the woman, who is in her mid-forties, was yet to be acertained, he added.