"The festival organised by Sri Sri Ravi Shankar will provide the country a window to the world as Swami Vivekanand's address did in Chicago in 1897," said Gupta, the Leader of Opposition in the Delhi Assembly.
Activists have raked up the question of serious environmental violations on account of the three-day event which is likely to be attended by about 35 lakh people.
Gupta said Congress' criticism of the event will "damage" India's image abroad. He also defended the Central government's support to its organisers for preparations and construction of a pontoon bridge by army.
"The government is bound to help such programmes irrespective of the religion involved. The AOL event cannot be an exception.
"When army can build bridges during Kumbh and Ardh Kumbh and help authorities organize programmes of such magnitude, there is nothing wrong in building a pontoon bridge for the event," he added.