Five children, including two siblings, were killed and another was critically injured in the wall collapse in Dallupura area.
Plot owner Bijender Singh, 50, and contractor Bhanwar Singh, 48, were arrested, they said.
A case under Sec 304 (culpable homicide not amounting to murder) and 288 (negligent conduct) of IPC has been registered against them yesterday.
The six children, aged below ten years, were playing in the vacant plot when the mishap took place. All of them were trapped under the debris. Rescue workers took them to hospital where five were declared brought dead.
The deceased were identified as Amit (7), Kanchan (7), Ankit (6), Baby (4) and Aditya (2). The injured has been identified as Saraswati (4).
Officials said construction of a boundary wall of around ten ft height was being carried out in the plot. "The wall collapsed adjacent to Hindon drainage," they said.
