The Nuclear Security Summit, which was opened by President Obama recently, has focused on many issues. I feel focus of the world should be on total elimination of nuclear weapons from the planet. The dangers posed by nuclear weapons are known to all but nobody is agreeing on the first step of securing nuclear materials for us to, then, go on to the next step of total nuclear disarmament. That in turn would initiate the process of total elimination of these destructive weapons. The horrors of Hiroshima and Nagasaki are still fresh in our minds. One of the contributory causes of global warming and other natural disasters is the on going testing of these weapons. -ZEESHAN AHMED KHAN, Karachi, April 17.