You are you
and I am I
If we meet its beautiful,
All cities are mad: but the madness is gallant. All cities are beautiful: but the beauty is grim. Christopher Morley
Every city, can be summed up in a single word, the essence of the city,
Similarly two cities aligned and fused would mean empowering them to omnipotence.
Moving Mumbai that screams money next to Delhi that houses power would be an interesting experiment, not only are complimentary but are symbiotic too.
The danger would be the rest of the country would be rendered orphan, and we the illusion of sovereign democratic republic of India would cease to exist as the multi-manifestation we exist today.