To rig an election in a multi party democracy like India, you don’t have to hack all 1.6 million EVMs. No need to tamper even 10% (160,000) as mentioned.
Any party which can tamper 38000 to 54000 EVMs (2.5% to 3.5%)will sweep the election. (1/n)
It is not necessary for a party to tamper the EVMs in every constituency. They’ll do it only where they feel they have a chance, but competition is tough and that will eliminate the suspicion. Wherever they can use and manipulate the govt machinery, it is not a tough task
In the last Lok Sabha election, 331 winners won with less than 50% of total votes polled in their constituencies; 99 winners got less than 40% and 4 winners have won with less than 30% of total votes polled in their constituency.
In UP, in 2014, The SP and BSP combined represented 42% of vote share. In Bihar RJD scored 20.14% vote share. The representation of regional parties remained equal – at 212 seats – with the same vote share (46.6% against 46.7% in 2009).So when they make strong alliances, winning margin reduces.
An EVM can store 2000 votes. If 850 voter/EVM is calculated and if 50% of the 850 votes are manipulated, with 50 rigged EVMs, one candidate can score 25000 more votes in a constituency. Here, he is not only scoring additional 25000 votes, but reducing that much from other candidate(s) which gives added advantage. And in many cases that is the winning margin