Former Prime Minister Manmohan Singh on Sunday accused Prime Minister Narendra Modi of resorting to 'jumla' by promising to double farmers' income and said the Modi government had messed up the economy.Addressing the Congress plenary here, he said the BJP-led government had created problems for small and medium industry and also the informal sector."The BJP government has messed up the economy. When Modiji was campaigning (in 2014), he made lots of tall promises. Those promises have not been fulfilled," Singh said.The Congress leader slammed demonetization and the way the Goods and Services Tax was implemented and said the Bharatiya Janata Party had promised to create two crore jobs every year."We have not seen even two lakh jobs. Instead, the ill-thought and ill-considered move with regard to demonetization and hastily put forward legislation of GST has destroyed many jobs," he said."Modiji himself said we will double farmers income in six years. Now if you have to double farmers incomes in six years, you need a growth rate of 12 per cent at the minimum. And that is unthinkable. Therefore it is one of those statements which is a 'jumla'," Singh added.The three-day plenary will end on Sunday with address by Congress President Rahul Gandhi.