Which constitutional amendment gave Delhi the name National Capital Territory?

Explanation

Under the new Article 239AA inserted by the 69ᵗʰ Constitution (Amendment) Act, 1991, the Union Territory of Delhi was named the National Capital Territory (NCT) of Delhi and its administrator was designated as the Lieutenant Governor. Along with this, provisions were also made for the establishment of a Legislative Assembly for the NCT of Delhi and a Council of Ministers responsible to it.