The trade agreement that the US and China announced on Tuesday, limiting China’s clothing exports for the next three years, makes official what had already been happening: the return of quotas, at least for the world’s largest textile and apparel power.Even before Tuesday’s pact, the US had unilaterally imposed a series of emergency limits on 19 categories of garments and textiles, curtailing growth in exports to 7.5 per cent a year despite an end to the global system of quotas last January 1. The European Union reached its own agreement with China in the summer to limit exports. The last-minute deal on Tuesday removed a persistent thorn in Chinese-American relations shortly before President Bush is to visit Beijing at the end of next week. And it ended the uncertainties that have caused multinational retailers like Wal-Mart to hold back on big purchases from Chinese suppliers for fear the shipments would be stopped by American customs officials.The pact, concluded in London by Commerce Minister Bo Xilai of China and Rob Portman, the US trade representative, allows China to increase its exports slightly each year until 2008, but puts limits on the growth and includes a wider range of products than those already affected by restrictions. Later on Tuesday, President Bush called the US trade imbalance with China ‘‘bothersome’’ to some people and said that Beijing should do more to open the country’s markets and promote greater currency flexibility.The textile deal negotiated in London specifically covers 34 categories, replacing limits on 19 categories and adding 15 more. All of these would be allowed to grow by 10 percent in 2006, by 12.5 percent in 2007 and by 15 to 16 percent in 2008. Chinese exports surged as much as tenfold in some categories at the beginning of this year.The impact of the agreement on consumers is expected to be small. Even before the quotas expired last year, Wal-Mart was buying less clothing from China than from Bangladesh, for example, where seamstresses earn a third of what their counterparts in China do.Poorer nations like Bangladesh and India, which have had no quotas on their exports since January, are expected to continue to increase their shipments. Manufacturers are also likely to take the initial steps of cutting and sewing garments in China and then ship them elsewhere for final assembly, thereby bypassing quotas. This was a common practice before the expiration of global quotas on Jan. 1, and a practice that US unions denounced. — NYT