For starters in the history of Ancient India, the following passages from various Greek chronicles and travel logs are strictly recommended before coming into any hilarious hypothesis.
Ancient India @Megasthenes
India, which is in shape quadrilateral, has its eastern as well as its western side bounded by the great sea, but on the northern side it is divided by Mount Hemodos from that part of Skythia which is inhabited by those Skythians who are called the Sakai, while the fourth or western side is bounded by the river called the Indus, which is perhaps the largest of all rivers in the world after the Nile. The extent of the whole country from east to west is said to be 28,000 stadia, and from north to south 32,000. Being thus of such vast extent, it seems well-nigh to embrace the whole of the northern tropic zone of the earth, and in fact at the extreme point of India the gnomon of the sundial may frequently be observed to cast no shadow, while the constellation of the Bear is by night invisible, and in the remotest parts even Arcturus disappears from view. Consistently with this, it is also stated that shadows there fall to the southward
Ancient India @Arrian
But Ctesias of Cnidus affirms that the land of India is equal in size to the rest of Asia, which is absurd; and Onesicritus is absurd, who says that India is a third of the entire world; Nearchus, for his part, states that the journey through the actual plain of India is a four months' journey. Megasthenes would have the breadth of India that from east to west which others call its length; and he says that it is of sixteen thousand stades, at its shortest stretch. From north to south, then, becomes for him its length, and it extends twenty-two thousand three hundred stades, to its narrowest point. The Indian rivers are greater than any others in Asia; greatest are the Ganges and the Indus, whence the land gets its name.
Ancient India @Plutarch
As for the Macedonians, however, their struggle with Porus blunted their courage and stayed their further advance into India. For having had all they could do to repulse an enemy who mustered only twenty thousand infantry and two thousand horse, they violently opposed Alexander when he insisted on crossing the river Ganges also, the width of which, as they learned, was •thirty-two furlongs, its depth •a hundred fathoms, while its banks on the further side were covered with multitudes of men-at‑arms and horsemen and elephants. 3 For they were told that the kings of the Ganderites and Praesii were awaiting them with eighty thousand horsemen, two hundred thousand footmen, eight thousand chariots, and six thousand fighting elephants. And there was no boasting in these reports. For Androcottus, who reigned there not long afterwards, made a present to Seleucus of five hundred elephants, and with an army of six hundred thousand men overran and subdued all India.
.........................................................................................................................................................
From the above passages, what is the only thing obvious here? The answer is quite simple. The Greek records of ancient India did not merely stop at Indus basin. The further they advanced, their idea of geographical India became gradually more transparent. The Greek expression of the territory beyond East of Indus was strictly a geography called 'India'. just as anything beyond East of Aegean sea was Asia whose eastern limits were yet to be explored by them.
