The incident happened in Lisare gate police station area here, they said.
Nazia aka Lajjo was strangulated with an electricity wire by her brother Mohammad Yasin, aged around 25-26 years, after which he surrendered himself before police.
The girl was having an affair with a neighbour over which Yasin was angry, police spokesperson D K Dwivedi said.
The body has been sent for postmortem, he said, adding, the accused has been arrested on the basis of complaint by their family members.