Gst registration in another state

temporary work for few months

You may take registration as a Casual Taxable person in that State for temporary work, it's for 90 days , you may get extension another 90 days ( total  6 months )  so just confirm.  Casual  Taxable person is define under section 2(20) of the CGST Act . 

Take others opinion  as well .  

What is the nature of work??

You can do it form Delhi also by charging and paying IGST