Can an NRI purchase securities by subscribing to the public issue (IPO)?

An NRI is permitted to subscribe to the public issue provided the company offering the issue allows NRI to participate in its issue. They detail related to this is published in the Red Herring Document (RHP) of the IPO.

Note that most companies do not permit NRIs to invest in their IPO due to additional compliance costs.

NRIs can also only apply in an IPO through the ASBA facility provided by the bank where they have their NRI bank account. NRI's can't apply in IPO through an online broker like Zerodha as they use UPI as a payment gateway which is not available to NRIs.

An NRI does not require any PIS approval to apply for a public issue and can invest using Non-PIS NRE or NRO bank, Trading and Demat accounts depending on whether an NRI wants to invest on a repatriation basis or a non-repatriation basis.