Calcutta, March 5: Less than a fortnight to her HS examinations, Khana Ghosal committed suicide last night be- cause her sister apparently ticked her off for seeing television instead of studying.

The 18-year-old girl of Joynagar in South 24-Parg- anas had got first-division marks in Madhyamik.

Arati (name changed on request), who is now writing her secondary examinations, said her sister became “sentimental” when she asked didi to emulate her.

“See my seriousness. I am working out sums as my mathematics exam is slated for tomorrow,” she told Khana.

District superintendent of police S.N. Gupta said: “We are yet to know what actually prompted Khana to drink poison. We are still speaking to her sister, though in a restrained manner.”

Their father Bimal Ghosal, a clerk in a private firm, was at work when the sisters had the tiff.

Mother Minati had gone to a neighbour’s house.

At Sehranpur village, around 70 km from Calcutta, the Ghosals, who own about 10 bighas of agricultural land, are considered affluent.

They had a large stock of pesticides at home for their farmland.

On returning home, Minati saw her elder daughter writhing in pain and frothing at the mouth. As she cried out, Arati, busy in her last-day revision, came running from an adjoining room.

Neighbours took her to hospital where she was declared dead.

“She was as good as my younger daughter in her studies. I can’t believe what has happened,” Bimal said.