We report on studies of an In0.12Ga0.88N/GaN structure with three 35 Angstrom thick quantum wells (QWs) grown by metalorganic vapor phase epitaxy with employment of mass transport. The mass-transport regions demonstrate a threading dislocation density less than 10(7) cm(-2). The photoluminescence (PL) spectrum is dominated by a 40 meV-narrow line centered at 2.97 eV at 2K. This emission has a typical PL decay time of about 5 ns at 2 K within the PL contour. An additional line with longer decay time (about 200 ns) is observed at an energy about 2.85 eV. The position of this line shifts towards higher energies with increasing excitation power. The data are consistent with a model, where the PL originates from at least two nonequivalent QWs, which could be realized due to a potential gradient across the layers.