The new interactive edition, called "Water: Our Thirsty World," can be downloaded only until 2 April. The US-based environment and science monthly said the offer was to commemorate the UN's World Water Day which falls on 22 March.

The magazine recently reported that 1 billion people worldwide have no access to clean water and 3.3 million people die from water-related health problems annually. The new National Geographic issue uses interactive maps and charts to explain the water situation. The company has set up a web portal to offer further information on the issue.