Why is the rupee getting weaker against the $?

US Economy is growing (~2.5%)

Less 'Quantitative Easing', no $ being printed.

Bond yields have increased demand for $.

India doesn't allow other countries to hold/trade with Rs.

Over-dependance on inflows, without a convertible currency.

Institutionally- index futures are being sold by FIIs.

Individually- high inflation rates = NRI $ staying away from India.

US interest rates may decrease soon. This will help the Rs.