Kautilya's Arthashastra 2.24.5

2.24.5

ṣoḍaśadroṇaṃ jāṅgalānāṃ varṣapramāṇam, adhyardham ānūpānāṃ deśavāpānām, ardhatrayodaśāśmakānām, trayoviṃśatir avantīnām, amitam aparāntānāṃ haimanyānāṃ ca, kulyāvāpānāṃ ca kālataḥ //

The quantity of rain that falls in the country of jángala is 16 dronas; half as much more in moist countries (anúpánám); as to the countries which are fit for agriculture (désavápánam);--13½ dronas in the country of asmakas; 23 dronas in avantí; and an immense quantity in western countries (aparántánám), the borders of the Himalayas, and the countries where water channels are made use of in agriculture (kulyávápánám).