The program was begun in the 21 stations of just one line, but organizers hope to expand it to the entire metro network, which daily carries nearly five million passengers.
Programmu sāka īstenot vienas metro līnijas 21 stacijā, taču organizatori cer to paplašināt, lai aptvertu visu metro tīklu, kas ik dienas pārvadā gandrīz piecus miljonus pasažieru.