Hi, Saimendra!
Taxis to Auli may not be available due to heavy snow in the region, however you can try booking yourself a seat in the cable car available from Joshimath to Auli.
Hi Saimendra! Yes, taxis are plying for commuting from Chopta to Auli. However, due to snow and weather conditions, roads may be blocked and availability of cabs may be less. It is therefore advisable that you make a booking in advance from the taxi services of the area. Happy Travelling!