The matter is being investigated.
A teacher and two students of Dyal Singh College were injured in a small explosion during a laboratory experiment, an official said.
Guest teacher Dr Nisha Agarwal and two girl students were injured in the accident.
Ms Agarwal has been admitted in AIIMS Trauma Centre while the students were sent home after first aid in the college, Delhi University constituent.
The teacher was demonstrating the distillation method in organic chemistry to a first-year BSc (Physical Science) class, students said.
During the experiment, the flask's temperature increased when Agarwal poured mercury into the chemical, leading to the explosion.
Ms Agarwal suffered serious injuries, including burns to her face.
The students suffered minor injuries and had to be given first aid. The matter is being investigated, the official said.
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