He expressed serious concern over the situation, particularly the impact on job creation.
Mr Singh, in his intervention at the Congress Working Committee (CWC) meet, spoke about the decline in the economic growth as depicted in the last quarter GDP numbers.
He said the slow down was primarily due to demonetisation announced by Prime Minister Narendra Modi on November 8 last year.
He said the Gross Value Addition (GVA) is the true sub-measure of economic activity and it has experienced a steep and sustained fall.
"Private sector investment has collapsed and the economy is running on just one engine of public spending," he said at the meeting, chaired by Congress President Sonia Gandhi.
Mr Singh said the GVA growth of industry has fallen from 10.7 per cent in March 2016 to just 3.8 per cent in March 2017, a decline of nearly seven percentage points of growth.
"The most worrisome aspect of all this is the impact on job creation. Jobs have been extremely hard to come by for the youth of the nation," he said.
The former Prime Minister noted that the construction industry, which is one of the largest employment generators in the country, has suffered contraction. This, he said, "implies loss of millions of jobs for the nation's workforce".