Dear Stuti,
As per Delhi Shops and Establishments Act, 1954
(5) “commercial establishment” means any premises wherein any trade, business or profession or any work in connection with, or incidental or ancillary thereto is carried on
Your travel agency is a Commercial Establishment and will come under the purview of Delhi Shops and Establishments Act, 1954 and hence registration is mandatory under Section 5 of the Delhi Shops and Establishments Act, 1954.
Regards
Arun