Sir: There has been an alarming increase in the use of e-cigarettes among teenagers. Some teenagers think it cool to use e-cigarettes which is extremely dangerous for human health. In the United States today, one in 20 adults, or more than 10 million people use e-cigarettes while three times as many as smokers. We must take immediate actions to protect our children from such products which are injurious to health. ZIMAL GULRAIZ Karachi