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The post-reionization $(z \le 6)$ neutral hydrogen (HI) 21-cm intensitymapping signal holds the potential to probe the large scale structures, studythe expansion history and constrain various cosmological parameters. Here weapply the Tapered Gridded Estimator (TGE) to estimate$P(k_{\perp},k_{\parallel})$ the power spectrum of the $z = 2.28$ $(432.8\,{\rm MHz})$ redshifted 21-cm signal using a $24.4\,{\rm MHz}$ sub-band drawnfrom uGMRT Band 3 observations of European Large-Area ISO Survey-North 1(ELAIS-N1). The TGE allows us to taper the sky response which suppresses theforeground contribution from sources in the periphery of the telescope's fieldof view. We apply the TGE on the measured visibility data to estimate themulti-frequency angular power spectrum (MAPS) $C_{\ell}(\Delta\nu)$ from whichwe determine $P(k_{\perp},k_{\parallel})$ using maximum-likelihood whichnaturally overcomes the issue of missing frequency channels (55 \% here). Theentire methodology is validated using simulations. For the data, using theforeground avoidance technique, we obtain a $2\,\sigma$ upper limit of$\Delta^2(k) \le (133.97)^2 \, {\rm mK}^{2}$ for the 21-cm brightnesstemperature fluctuation at $k = 0.347 \, \textrm{Mpc}^{-1}$. This correspondsto $[\Omega_{\rm HI}b_{\rm HI}] \le 0.23$, where $\Omega_{\rm HI}$ and $b_{\rmHI}$ respectively denote the cosmic \HI mass density and the \HI biasparameter. A previous work has analyzed $8 \, {\rm MHz}$ of the same data at$z=2.19$, and reported $\Delta^{2}(k) \le (61.49)^{2} \, {\rm mK}^{2}$ and$[\Omega_{\rm HI} b_{\rm HI}] \le 0.11$ at $k=1 \, {\rm Mpc}^{-1}$. The upperlimits presented here are still orders of magnitude larger than the expectedsignal corresponding to $\Omega_{\rm HI} \sim 10^{-3}$ and $b_{\rm HI} \sim 2$.

Towards 21-cm Intensity Mapping at $z=2.28$ with uGMRT using the Tapered Gridded Estimator I: Foreground Avoidance