The Select Citywalk Mall, at Saket in New Delhi, hosted a flash mob - a group of people who assemble suddenly in a public place, perform some act and melt into the crowd - of a different kind on Sunday. A group of women in the 55-75 age group gathered for about half an hour, cheered and danced, "celebrating life" in general. It turned out to be an advertising gig organised by Ashiana Housing, a real estate firm, which has a host of housing projects for older citizens in cities such as Bhiwadi, Jaipur and Lavasa, besides one under construction in Chennai.