  The short gamma-ray burst (GRB) 170817A was the first GRB associated with a
gravitational-wave event. Due to the exceptionally low luminosity of the prompt
$\gamma$-ray and the afterglow emission, the origin of both radiation
components is highly debated. The most discussed models for the burst and the
afterglow include a regular GRB jet seen off-axis and the emission from the
cocoon encompassing a "choked" jet. Here, we report low radio-frequency
observations at 610 and 1390~MHz obtained with the Giant Metrewave Radio
Telescope (GMRT). Our observations span a range of $\sim7$ to $\sim152$ days
after the burst. The afterglow started to emerge at these low frequencies about
60~days after the burst. The $1390$~MHz light curve barely evolved between 60
and 150 days, but its evolution is also marginally consistent with a
$F_\nu\propto t^{0.8}$ rise seen in higher frequencies. We model the radio data
and archival X-ray, optical and high-frequency radio data with models of
top-hat and Gaussian structured GRB jets. We performed a Markov Chain Monte
Carlo analysis of the structured-jet parameter space. Though highly degenerate,
useful bounds on the posterior probability distributions can be obtained. Our
bounds of the viewing angle are consistent with that inferred from the
gravitational wave signal. We estimate the energy budget in prompt emission to
be an order of magnitude lower than that in the afterglow blast-wave.
