Pandals and idols inspired by a particular theme have been the hallmark of many community or Sarbajanin Pujas in Kolkata since the 1990s. Puja committees decide on a particular theme, whose elements are incorporated into the pandal and the idols. Popular themes include ancient civilizations like the Egyptians or Incas. Contemporary subjects like the RMS Titanic and Harry Potter have also been the subject in some pandals.
The design and decoration is usually done by art and architecture students based in the city. The budget required for such theme-based pujas is often higher than traditional pujas. They attract crowds and are well-received. Inspired by Kolkata, theme-based pandals are becoming popular in cities in neighbouring states, particularly Orissa (see above).
Experimentation with the idols does not happen much outside Calcutta. Rapid growth of competitiveness in theme pandals, and also rapid growth of massive billboards that come up at strategic junctions, prior to Puja and allied commercial activities, has also created a cultural backlash from city's traditional Puja pandals, which now claim, "We do not do theme puja, we do Durga puja,”, according to one hoarding put up in Salt Lake, Kolkata.