Is the Tashkent flight coming into DEL Terminal 3 and the one to BKK leaving out of DEL Terminal 3?

At least in some cases it’s possible to transit DEL without clearing immigration to enter the country. It may be more possible if being hand-baggae-only pax and having an onward boarding pass issued already for the flight out of India.

At least in older years, the transfer desk at DEL was sort of more airline agnostic and whomever was staffing it would liaison with whichever airline was of relevance for the passengers showing up for international transfers.