The blast apparently took place in a garbage dump near 'Hindu Para,' an area which has a large Hindu population, police officials said.
"Initially we can confirm six people have been injured and one has been killed due to the explosion that occurred at a time when there was a rush in the area," an official said.
Another channel reported that the bomb was planted in a motorcycle parked near the Hindu Para locality and the number of casualties could be higher.
"The bomb disposal squad and emergency services have rushed to the site to handle the situation," the police official said.
He said the explosion occurred around the area which is one of the oldest areas of Karachi and houses commercial centres and residences as well.
Karachi has largely been safe from the mass scale terrorism attacks being carried out in the country by militants.
