We present a theoretical study of the Doppler broadened Y-type six-level atomic system, using a density matrix approach, to investigate the effect of varying control field wavelengths and closely spaced hyperfine levels in the 5P3/25P3/2 state of 87Rb. The closely spaced hyperfine levels in our six-level system affect the optical properties of Y-type system and cause asymmetry in absorption profiles. Depending upon the choices of π -probe, σ+-controlσ+-control and σ−-controlσ−-control fields transitions, we consider three regimes: (i) perfect wavelength matching regime (λp=λc1=λc2λp=λc1=λc2), (ii) partial wavelength mismatching regime (λp≠λc1=λc2λp≠λc1=λc2), and (iii) complete wavelength mismatching regime (λp≠λc1≠λc2λp≠λc1≠λc2). The complete wavelength mismatching regime is further distinguished into two situations, i.e., λc1<λc2λc1<λc2 and λc1>λc2λc1>λc2. We have shown that in the room temperature atomic vapor, the asymmetric transparency window gets broadened in the partial wavelength mismatching regime as compared to the perfect wavelength matching regime. This broad transparency window also splits at the line center in the complete wavelength mismatching regime.