BENGALURU (Reuters) -Indian shares saw their worst one-day fall since April, tumbling nearly 2% on Thursday, with metal stocks leading losses on easing supply problems. The blue-chip NSE Nifty 50 index and the benchmark S&P BSE Sensex fell 1.94% and 1.89% to 17,857.25 and 59,984.70, respectively. Copper and aluminium prices hit multi-month lows on improving availability, pulling down the Nifty metals index 3.4%. [MET/L] “The fall in commodity prices is starting to reflect in metal stocks,” said Vijay L Bhambwani, head of research at Equitymaster, adding that the global prices would further ease in coming months. Monthly expiry of futures and options also spurred selling, analysts said, adding that a fall below 18,000 in the Nifty forced some investors to cover their positions. India’s benchmark stock indexes have risen more than 25% this year, driven by massive liquidity and huge retail participation, raising concerns that some companies are over-valued. Morgan Stanley downgraded Indian equities to equal weight from overweight on Thursday due to expensive valuations and said it expects the market to consolidate ahead of potential “short-term headwinds”. The downgrade follows similar moves by Nomura and UBS. Shares of India’s largest port operator Adani Ports fell as much as 8.7% on lower quarterly profit as well as its move to pull out of Myanmar. Shares of IndusInd Bank rose 2.9% on strong September-quarter profit and improving growth prospects and was the top gainer on the Nifty 50 index. The Nifty bank index and the public sector bank index were among the top drags, falling 3.3% and 5.2%, respectively. Meanwhile, digital payments leader Paytm boosted the size of its initial public offering to 183 billion rupees ($2.44 billion) ahead of the country’s largest stock market listing. Reporting by Nallur Sethuraman in Bengaluru; Editing by Lisa Shumaker