A low solids-content slurry for polishing (e.g., chemical mechanical planarization) of substrates comprising a dielectric and an associated method using the slurry are described. The slurry and associated method afford high removal rates of dielectric during polishing even though the slurry has low solids-content. The slurry comprises a bicarbonate salt, which acts as a catalyst for increasing removal rates of dielectric films during polishing of these substrates.