Supermarket operators were clearly at the bottom of the pile on Tuesday after market researcher Kantar published new figures showing a stagnating food retail environment.Fraser McKevitt, head of retail and consumer insight at Kantar, said: "For the first time ever we've seen the average basket of everyday goods bought today costing exactly the same as it did a year ago.Sainsbury's fell 15p to 263.8p on the heels of those figures, which showed sales at the chain dropped 1.8% in the 12 weeks to 14 September, while Morrisons' sales dipped 1.3%, dragging its shares down 4.4p to 174.6p.German discounter Aldi saw an increase in its sales by 29.1% for the year ended in September compared to the previous year. Lidl raised its sales by 17.7% in the same time period thanks to its discounts.Shares in Tesco, which on Monday was forced to revise its profit forecasts after an accounting error, reversed 8.5p to 194.5p as its sales declined 4.5%.Trader David White at Spreadex said: "Investors are today saying of the supermarkets that the rate at which earnings will change over time is increasing to the downside."On the positive side of things, the latest Chinese PMI figures came in better than expected.The Chinese news buoyed miners, which were among the few risers. Rio Tinto lifted 49.5p to 3108p, Randgold Resources gained 47p to 4312p, miner and commodity trader Glencore increased 2.35p to 344.25p and BHP Billiton moved 11p higher to 1741.5p.