Warning: Long answer ahead
Let's see a map of the Western Ghats, for those who don't know the terrain and geography of India:
So, by some magic and handwavium, you managed to substitute the Western Ghats with the Himalayas and the monsoon with El Nino. The results are gruesome.
The Himalayas are still cold as ever, due to the fact that the Himalayas do not behave like the Polar ice caps. The polar ice caps are frigid as they are located at the Earth's poles, where there is little direct sunlight. On the other hand, the Himalayas are cold as they reach way up into the atmosphere. Literally, "way up". Mt. Everest pierces the stratosphere. Similarly, I can imagine tall peaks like K2 and Kanchenjunga to atleast be really near the border of the stratosphere, if not in it.
This means that your subcontinent will basically be really cold and windy. Let's not forget that the Himalayas actually sit in the jetstream, being so tall and large. And forget the jetstream, the Himalayas now stand in the way of trade winds from the Arabian Sea, and the Bay of Bengal. And don't forget, hill stations in India (and around the world), even at low altitudes, near the Himalayas always snow, in some cases, even in summer. Basically long story short, South India is now basically Siberia on a budget.
That does not address the second part of the question, though:
Contrary to what you would believe, El Nino won't favor rain clouds, except for hurricanes. This is a massive problem for India. As of now, 40% of India's annual water being used in agriculture comes from monsoon rain. So long story short, you have a starving nation with a ton of food deficit, droughts and blah blah blah. I haven't even started on the effects of strong turbulent winds on the climate. As in a previous answer of mine about the climate of Gondwana, India would likely suffer from a ton of droughts.
El Nino, while not favorable for raincloud formation, paradoxically catalyses hurricane formation. As El Nino is
just a river of hot water in the ocean , a warm ocean band, you have more moisture in the air over the Arabian sea and Bay of Bengal. However, as the El Nino also warms up the air above it, the air is able to hold a b***load of moisture. This means that the moisture is held up in the air for a long time, unless the trigger is pulled, and the moisture suddenly condenses, and a hurricane is formed.
Also, even if the moisture was prematurely released before hurricane formation, you would still end up with a ton of thunderstorms. Cold air from the Himalayas and El Nino air would override each other in the subcontinent, forming supercells. In other words, India now has:
In other words, A perfect hellscape.