The excavations conducted in the subsequent years established that a civilizations possessing a high standard of art & craftsmanship & a well-developed system of pictographic writing had existed about 2250 BC., in the Indus Valley for a considerable period before the arrival of lndo-Aryans. Moenjodaro and other sites of Indus Valley have provided very significant archaeological results and given us considerable information about the civilizations of the original inhabitants of the subcontinent.
The excavated ruins at Moenjodaro, which have so far been subjected to the attention of archaeologists, cover an area of about 100 hectares.
Well-constructed and covered drainage systems and neat parallel streets, laid out in an orderly design, suggest a developed and major civilizations, far ahead of most of the rest of the ancient world. Europe at the time, more than 4,500 years ago, had barely emerged from the Stone Age. Moenjodaro, however, yields its secrets reluctantly, It will be sometime before a really comprehensive picture of the life of the people begins to emerge.
The economy of the cities of Moenjodaro was based upon the fertile valleys of the major rivers of the Indus Basin & the easy means of communication and transportation which these rivers afforded. As such, agriculture was the main occupation of the people of these regions. There is evidence to show that wheat, barley, seasamum, dates and cotton were cultivated. The farmers depended on the annual rains and floods for the irrigation of their fields. The architecture of the Moenjodaro period is plain & utilitarian. There are neither imposing temples nor royal tombs. It seems that the aim of the city builders was to make life comfortable rather than luxurious. No definite answer cm be given to the question, as to who were the people who lived in Moenjodaro. But it is certain that they were of non-Aryan racial stock and highly civilized.
Among the causes for the decay and desertion of these ancient cities of lndus Valley civilizations after 1800 B. C., progressive desiccation of the Valley may have been one. Another possibility may be the grow-ing danger of floods which compelled the inhabitants to evacuate these cities. There was a remarkable dearth of weapons of defence and war and it is probable that those rich cities with their un-warlike mercan-tile population were either ransacked by the invading tribes from the neighbouring hilly regions or that the inhabitants were compelled to migrate to more fertile valleys when dry & arid climatic conditions started prevailing on the Indus Valley.
It is a paradox of facts that the ruins of Moenjodaro buried beneath the accumulations of five thou-sand years remained in an excellent state of preservation. But as soon as they were exposed from oblivion to the incredible gaze of the 20th Century, they were overtaken by water-logging and salinity. These two diseases, combined with the threat of bank erosion by the Indus River, pose a grim danger to the existence of one of the most valuable cultural legacies of the human race.
Measures to Save Moenjodaro have been devised by the Government of Pakistan with the help of UNESCO experts. As a part of an international appeal for assistance to preserve Moenjodaro, the Pakistan Post Office, in collaboration with the Authority for the Preservation of Moenjodaro (Pakistan), had arranged to bring out a series of special stamps for public motivation. The first issue of the \"Save Moenjodaro\" series, consisting of a set of five stamps in se-tenant, was brought out on 29th February, 1976. This was followed by a 20-Paisa stamp issued on 31st May, 1976 and a 65-Paisa stamp issued on 31st August, 1976. Earlier, on 16th September, 1963, a set of four stamps was issued on Archaeological Series, out of which one 13-Paisa stamp depicted Moenjodaro.
Now, Pakistan Post Office is issuing, on December 31, 1984, two special postage stamps of the denomination of Rs. 2/- each on Moenjodaro, in the World Heritage Monument series, as a part of Save Moenjodaro Campaign.