Do I need a transit visa for a non-interline ticket in India?

I hold a Chinese passport. I flew from Dhaka to Singapore on May 5th, with a transfer in Kolkata, India. I booked my flight on Tongcheng Travel, but the platform issued my tickets separately.Therefore, I hold two ticket numbers.I won't be checking any baggage. When I check in at Dhaka, Bangladesh, can you print two airline tickets for me?I am an air ticket from Indigo Airlines.I read the announcement from the embassy, which stated that if you stay within 24 hours and do not leave the customs area, you do not need a visa.