The distance between Delhi and Auli is around 500 km, and it takes approx 12-13 hours to reach by road. You can take a taxi or bus from Delhi to Joshimath, which is the nearest town to Auli.
The nearest railway station to Auli is Rishikesh Railway Station, which is around 250 km away. You can take a train from Delhi to Rishikesh and then take a taxi or bus to reach Joshimath.
Overall, the best way to reach Auli from Delhi is by road. The road journey is quite scenic, and you can enjoy the beautiful landscape on the way.
If you prefer to travel by air or train, then you can take a flight or train to the nearest airport or railway station, followed by a taxi or bus to reach Auli.