* SSEC -0.3%, CSI300 -0.7% SHANGHAI, April 6 (Reuters) - China stocks retreated on Tuesday, pressured by healthcare and consumer companies, as solid economic data raised worries of policy tightening. ** The CSI300 index fell 0.7% to 5,128.01 points at the end of the morning session, while the Shanghai Composite Index dipped 0.3% to 3,473.32. ** As of last close, the CSI300 had rebounded nearly 6% from a recent trough hit on March 25, while SSEC had gained more than 4% in the same period. ** Falling the most on Tuesday, the CSI300 healthcare index and CSI300 consumer discretionary index dropped 1.8% and 1.9%, respectively. ** Recent economic data has been robust, but analysts warn that it could lead to concerns of inflation and policy tightening. ** A recovery in China’s services sector picked up speed in March as firms hired more workers and business optimism surged, although inflationary pressures remained, a private sector survey showed. ** The Caixin/Markit services Purchasing Managers’ Index (PMI) rose to 54.3, the highest since December, and well above the 50-mark that separates growth from contraction on a monthly basis. ** If China’s inflation and GDP growth data, due later this month, far beat expectations, policy tightening worries will be kindled, Huaan Securities said in a report. ** Analysts said short-term sentiment was weighed by foreign investors becoming net sellers via the Stock Connect last week and as the issuance of new mutual funds slowed substantially. ** Around the region, MSCI’s Asia ex-Japan stock index was firmer by 0.28%, while Japan’s Nikkei index fell 1.08%. ** The yuan was quoted at 6.5554 per U.S. dollar, 0.18% firmer than the previous close of 6.5675. ** As of 0345 GMT, China’s A-shares were trading at a premium of 32.87% over the Hong Kong-listed H-shares.