Over the last few months we have seen rupee depreciating from 43 levels to 54.30 which was the high recently, there are a lot of reason for this a few macro economic factors like :
Interest Rate Differentials
Large fiscal deficit,
Inflation
Global factors like euro zone crisis,because of which dollar has emerged as the strongest currency, However the currency has quickly bounced back to sub 51 levels, in a short span of time.

A few reason for this appreciation in Rupee:
1. RBI intervention to control falling rupee ( we had spent 15 billion USD to strengthen currency,which is almost 5% of our reserves) 
2. Hiking Non Resident External (NRE) deposit from 3 to 9.5% which has led to $9 billion Inflow (annual NRE flow is $3bn)
3.FDI in single brand retail approved.
4.Hiking Import duty on gold from 300Rs/10 gm to 3% of the total Imports, which is why rupee has gone below 51 today.

As inflation is at a 7.47% for december, which is at a 24month low, the RBI can be tempted to cut CRR and going forward the Interest rates, which will bring huge FII inflows an strengthen currency further.

I expect rupee to go to 50.5 within next few days and consolidate at levels between 49-50.5 for rest of the year.