Expressing concern over the weakest monsoon since 2009, the Reserve Bank today said rainfall deficit of 21 per cent is likely to hit production of kharif crops, mainly coarse cereals and pulses, and could put pressure on prices of these commodities.Though monsoon risks to overall economic growth could be limited due to small share of agriculture output in GDP, the impact may be significant because it affects the poor through inflation and income, RBI noted in its 'First Quarter Review of Monetary Policy 2012-13'.Noting that the impact of the monsoon will emerge more clearly in the coming weeks, RBI said that monsoon rainsduring this year have been slightly better than they were during the drought year of 2009.According to RBI, deficit rains have also affected water level in the 84 reservoirs under the Central Water Commission (CWC). The storage was 24 per cent of capacity on July 26,this year, as against 43 per cent in the same period in 2011.