  A gamma-ray burst, named GRB 221009A, occurred on 9 October 2022 and is the
brightest ever observed GRB, whose frequency is now estimated as once in 10,000
years. This GRB was reported to be observed from many space missions, VLF
receivers, and ground observations in optical and radio data. Additionally, a
strikingly large number of very high energy (VHE) photons associated with this
GRB were observed by the gamma-ray and cosmic ray observatory LHAASO. Though
gamma rays of cosmic origin usually tend to be absorbed by the atmosphere, the
high fluence of this GRB, along with the observation of more than 5000 VHE
photons (0.5 to 18 TeV) by LHAASO from the ground, emphasises the need to
explore other possible ground observations of this GRB.
  The present paper examines the effect of this GRB using gamma-ray data in a
low energy range (0.2-6) MeV obtained using NaI (Tl) detectors located at
Tirunelveli (Geographic coordinates: 8.71{\deg}N, 77.76{\deg}E), India. With RA
= 288.3{\deg} and Dec = 19.8{\deg}, the exceptionally bright fluence of this
GRB was geographically centred on India. We report no significant change in the
observations associated with GRB 221009A. We discuss the extent of attenuation
of gamma-rays in the atmosphere that could explain the reported observations.
Further, we investigate the likelihood of ground observation of gamma-rays
($<$10 MeV) for a much more intense hypothetical GRB, and estimate the
parameters, such as distance, fluence, and isotropic energy of such a GRB.
