"This is wonderful news and I hope it will make people look at heritage differently and open up the doors to many other old cities, which have the potential of becoming World Heritage Cities," noted urban planner and architect AGK Menon told PTI.
He expressed the hope that policy-makers and others would not consider heritage as a burden and "anti-development".
The city of Delhi was nominated by India in 2015 for the same category but the Centre pulled out of the race towards the end of the process.
Menon, former convener of the Delhi Chapter of the heritage group, INTACH, which had prepared the dossier for Delhi's nomination, said the Ahmedabad Municipal Corporation (AMC) and the state government as well as the people all worked "very hard to make this dream a reality".
The honour, he said, was a "lesson" for civic bodies around the country, including in Delhi, to look at heritage as an asset as Ahmedabad did, and "preserve, conserve and restore" heritage sites for posterity.
The decision was taken during the ongoing 41st session of the World Heritage Committee in the Polish city of Krakow, which acknowledged the preservation efforts made by the city in keeping its historical fabric intact.
The city's historic characteristics include densely- packed traditional houses ('pols') in gated traditional streets ('puras') with features such as bird feeders, public wells and religious institutions.
Heritage activist Sohail Hashmi, who conducts regular walks in Old Delhi, was elated to learn about the recognition, but sounded a word of caution.
"It is indeed a moment of pride for all of us. But this achievement comes with a price. We know Delhi's nomination was withdrawn because many decision-makers thought it (the UNESCO tag) would hamper urban infrastructure expansion," he said.
He said it was ironical that the central government had recently approved an amendment to a heritage-related legislation to allow construction near protected monuments.
"So, tomorrow, if they try to build a flyover near an iconic heritage building, the UNESCO may withdraw the tag," Hashmi said.