The present invention provides an aqueous composition for coating substrates comprising: one or more emulsion copolymer, the emulsion copolymer being a copolymerization product of a monomer mixture comprising a monomer of formula I, wherein R1 is hydrogen or methyl, X is a divalent organic alkylene oxide group, n is an integer ranging from 1 to 50 and R2 is hydrogen or an aliphatic or aromatic hydrocarbon group having from 1 to 20 carbon atoms, and a phosphate surfactant. When incorporated into a coating composition, the coating composition show both improved stain-resistance properties and anti-clogging properties.