  In the star formation process, the vital impact of environmental factors such
as feedback from massive stars and stellar density on the form of the initial
mass function (IMF) at low-mass end is yet to be understood. Hence a
systematic, highly sensitive observational analysis of a sample of regions
under diverse environmental conditions is essential. We analyse the IMF of
eight young clusters ($<$5 Myr), namely IC1848-West, IC1848-East, NGC 1893, NGC
2244, NGC 2362, NGC 6611, Stock 8 and Cygnus OB2, which are located at the
Galactocentric distance ($R_g$) range $\sim$6-12 kpc along with nearby cluster
IC348 using deep near-IR photometry and Gaia DR2. These clusters are embedded
in massive stellar environments of radiation strength $log(L_{FUV}/L_{\odot})$
$\sim$2.6 to 6.8, $log(L_{EUV})$ $\sim$42.2 to 50.85 photons/s, with stellar
density in the range of $\sim$170 - 1220 stars/pc$^2$. After structural
analysis and field decontamination we obtain an unbiased, uniformly sensitive
sample of pre-main-sequence members of the clusters down to brown-dwarf regime.
The lognormal fit to the IMF of nine clusters gives the mean characteristic
mass ($m_c$) and $\sigma$ of 0.32$\pm$0.02 $M_\odot$ and 0.47$\pm$0.02,
respectively. We compare the IMF with that of low- and high-mass clusters
across the Milky Way. We also check for any systematic variation with respect
to the radiation field strength, stellar density as well with $R_g$. We
conclude that there is no strong evidence for environmental effect in the
underlying form of the IMF of these clusters.
