Read the following passage carefully and answer question numbers 1 to 5?

The cities of the ancient Indus were noted for their urban planning, baked brick houses, elaborate drainage systems, water supply systems, clusters of large non-residential buildings, and techniques of handicraft and metallurgy. Mohenjo-Daro and Harappa very likely grew to contain between 30,000 and 60,000 individuals, and the civilization may have contained between one and five million individuals during its fluorescence. A gradual drying of the region during the 3rd millennium BCE may have been the initial stimulus for its urbanization. Eventually, it also reduced the water supply enough to cause the civilization's demise and disperse its population to the east.
Although over a thousand Mature Harappan sites have been reported and nearly a hundred excavated, there are five major urban centers: Mohenjo-daro in the lower Indus Valley, declared a UNESCO World Heritage Site in 1980 as "Archaeological Ruins at Moenjodaro”, Harappa in the western Punjab region, Ganeriwala in the Cholistan Desert, Dholavira in western Gujarat, declared a UNESCO World Heritage Site in 2021 as "Dholavira: A Harappan City", and Rakhigarhi in Haryana. The Harappan language is not directly attested, and its affiliations are uncertain, as the Indus script has remained undeciphered.