I lost my passport. How can I re-enter the UAE from India now after getting a new passport?

You should approach the UAE Embassy in New Delhi or Consulate in Mumbai to get a true copy of your valid UAE visa.

If they issue it, you can travel and enter the UAE. Upon your entry, the Dubai Airport officer may ask for a guarantor passport of your sponsor/PRO and that will be released after your visa is stamped on your passport.

You have to take your personal file print-out from Immigration and type visa stamping in lieu of the lost application from the typing center.

Get a signature/stamp from your sponsor and submit it at Immigration. No need for medical. Show your stamped passport at the airport and receive the guarantor's passport.

Alternatively, you can ask your sponsoring company to apply for a visit visa with all supporting documents (Police Certificate of your country with attestation and legal translation in Arabic) and stamp a visa in the same way mentioned above.

Later, you will have to exit with a visit visa to clear the visit visa file.