Values were log₁₀-transformed to handle the skewed distribution, then run through Jenks Natural Breaks optimisation — a cartographic algorithm that places three break-points to minimise within-class variance and maximise between-class variance (Goodness of Variance Fit ≈ 0.90). Jenks was applied state-wise rather than pooled, so thresholds reflect each state's own luminosity range. The bands can be read intuitively in terms of how brightly lit each AC is at night relative to the most urbanised seats: in Tamil Nadu, for instance, Moderately Urban ACs register at roughly 13% of Highly Urban brightness, Moderately Rural at about 5%, and Highly Rural at around 2.5% — a near tenfold drop at each step down the gradient.