We present the CIDA-UCM-Yale (Centro de Investigaciones de Astronomía, Universidad Complutense de Madrid, and Yale University) Survey (CUYS) for Hα+[NII] 6549,6584Åemission-line galaxies (ELGs) using objective-prism spectra. The most important properties of a catalogue with 427 entries and significant subsets are analysed. The complete sample contains 183 statistically confirmed ELGs in a sky area of 151 deg2 and redshift up to 0.14. We determine the parameters of the Hα luminosity function using the Hα+[NII] flux directly measured on the ELG spectra in this sample, and the star formation rate density derived is in agreement with values reported in the literature. Finally, we study the clustering properties of local star-forming galaxies relative to quiescent ones from different perspectives. We find that ELGs avoid dense regions of quiescent galaxies and we propose a power-law expression to parametrize the relation between star formation rate density and environment volume density of ELGs.