If a satellite has its own maneuvering capabilities, it can change its orbit (somewhat). These are mostly nanosats and cannot do that, so they'll stay in closely-related orbits. Spring-loaded separation from the launch vehicle will give them some difference, which will be magnified over time.

Some rideshare launches have multiple burns of the upper stage to put payloads in different orbits. The PSLV can do that, though I don't know if this one will.