The S&P/TSX composite index dropped 57.21 points to 14,278.55, with the market also held back by gold stocks, which gave up further ground as bullion prices continued to decline.
The Canadian dollar was up 0.12 of a cent to 89.33 cents US.
U.S. indexes were also lacklustre as the initial or "flash" Markit purchasing managers index for the United States fell to 55.5 in March from 57.1 in February, but still showed improving conditions for manufacturers. Readings over 50 in the purchasing managers index indicate growth.
The Dow Jones industrials shed 26.08 points to 16,276.69, while the S&P 500 index was 9.08 points lower at 1,857.44.
The Nasdaq was the biggest loser, down 50.4 points to 4,226.39 amid losses in biotechs and social media stocks. Facebook, for example, was down 4.67 per cent to US$64.10.
Data out earlier in the session showed that the preliminary version of HSBC’s purchasing managers’ index for China dropped to 48.1 in March from February’s 48.5. It was the lowest reading since July 2013 and was below consensus expectations of a modest rise. The worse than expected Chinese data suggested that the slowdown in the world’s second-biggest economy is deepening.
In the past, traders have reacted to bad Chinese economic news in a more positive light amid hopes that the Chinese government would take action to ensure it meets its growth target of about 7.5 per cent.
But that confidence has been shaken lately.
"It is very much a different policy backdrop, monetary and fiscal," said Craig Fehr, Canadian markets specialist at Edward Jones in St. Louis.
"It’s clear that officials in China will be far more tolerant of a little slower growth because there is a broader shift occurring where officials would like to see an economy that is far more domestic consumption based."
The gold sector was the leading decliner, down about 4.35 per cent as April bullion shed $24.80 to US$1,311.20 an ounce.
Gold prices initially spiked in the wake of Russia's invasion of Crimea earlier this month. But they backed off as any threat of military retaliation quickly evaporated while sanctions have been aimed at specific individuals, not the main Russian economy.
The metals and mining sector gave up early gains to move down 1.48 per cent while May copper was unchanged at US$2.95 a pound. Worries about China have pushed the sector down more than six per cent this month, making that group the leading loser, while copper prices have fallen more than 7.5 per cent.
The energy sector edged up 0.11 per cent as the May crude contract on the New York Mercantile Exchange gained 14 cents to US$99.60 a barrel.
The tech sector was ahead 0.47 per cent and BlackBerry (TSX:BB) was up 31 cents to C$10.50 ahead of earnings from the smartphone maker coming out on Friday. On average, investors expect the company to post revenue of $1.1 billion and a net loss of about 57 cents a share. That is down sharply from a year ago when BlackBerry posted revenue of $2.2 billion and earnings per share of 18 cents.
Utilities and financials also supported the TSX.