Our trip was over from the travel agency but yet we paid extra 4.5k bucks to go see Marhi at 11,000ft, 15 km below Rohtang pass(we couldn't go to Rohtang as it wasn't open) . You will have to get permit to go there, our driver managed it and mind you mostly altos have the permit to go there so if you are a big group then plan accordingly. Again you have to get the snow clothes and go there. We woke up at 3:00am to go up there as it gets crowded with time and more the delay more the crowd lesser the fun. We reached the point by 6:30am and enjoyed it to our fullest. It was mesmerizing with the snow covered mountains. It's an absolute delight and a must visit. You can see the white snow glistening from the sun and can relate to Roerich's paintings. This was by far the best part of the trip.
There are many activities available there like riding a yak, snow bike ride and skiing which all cost a lot each. We simply went for tire sliding ₹100 each which was an absolute hoot.
After spending about 2:30 hrs in the snow we headed back and were thankful that we got up early and came as the line now for going pass the permit was very longgg.
We headed back to Delhi in the evening.
Overall an absolutely amazing trip will cost a lot but was worth it.