Compounds of formula (I) are CRTH2 ligands, useful in the treatment of, inter alia, respiratory diseases: wherein R1 is fluoro, chloro, cyano or trifluoromethyl; R2 is hydrogen, fluoro or chloro; R3 is hydrogen, fluoro, chloro or trifluoromethyl; X is —CH2—, —S—, —S(═O)— or —S(═O)2—; one of Y and Y1 is hydrogen and the other is —C(═O)R4, or —S(═O)2R4, or —CR5R6OR7 or a heterocyclic group selected from furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,5-oxadiazolyl, furazanyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,3-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, 1,2,4-thiadiazolyl, tetrazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, 1,2,4-triazinyl and 1,3,5-triazinyl any of which may be optionally substituted; R4 is an optionally substituted cyclic amino group having 5, 6 or 7 ring atoms which is linked to the carbonyl or sulfonyl through a ring nitrogen; R5 and R6 are independently hydrogen, (C1C3)alkyl, cyclopropyl, or R5 and R6 taken together with the carbon atom to which they are attached form a 3-6 membered cycloalkyl ring; and R7 is optionally substituted (C1-C6)alkyl or (C3-C6)cycloalkyl,