  The very high energy (VHE) gamma ray spectral index of high energy peaked
blazars correlates strongly with its corresponding redshift whereas no such
correlation is observed in the X-ray or the GeV bands. We attribute this
correlation to a result of photon-photon absorption of TeV photons with the
extragalactic background light (EBL) and utilizing this, we compute the allowed
flux range for the EBL, which is independent of previous estimates. The
observed VHE spectrum of the sources in our sample can be well approximated by
a power-law, and if the de-absorbed spectrum is also assumed to be a power law,
then we show that the spectral shape of EBL will be $\epsilon n(\epsilon) \sim
k log(\frac{\epsilon}{\epsilon_p}) $. We estimate the range of values for the
parameters defining the EBL spectrum, $k$ and $\epsilon_p$, such that the
correlation of the intrinsic VHE spectrum with redshift is nullified. The
estimated EBL depends only on the observed correlation and the assumption of a
power law source spectrum. Specifically, it does not depend on the spectral
modeling or radiative mechanism of the sources, nor does it depend on any
theoretical shape of the EBL spectrum obtained through cosmological
calculations. The estimated EBL spectrum is consistent with the upper and lower
limits imposed by different observations. Moreover, it also agrees closely with
the theoretical estimates obtained through cosmological evolution models.
