POST : https://www.kapadiya.net/wordpress/woocommerce-paypal-for-inr/

WooCommerce : Paypal for INR

add_filter('woocommerce_paypal_supported_currencies', 'add_aed_paypal_valid_currency');
function add_aed_paypal_valid_currency($currencies)
{
    array_push($currencies, 'INR'); /* YOUR CURRENCY */
    return $currencies;
}

add_filter('woocommerce_paypal_args', 'woocommerce_paypal_args_for_inr');
function woocommerce_paypal_args_for_inr($paypal_args)
{
    if ($paypal_args['currency_code'] == 'INR') {

        $convert_rate = getFromYahoo();

        $count = 1;
        while (isset($paypal_args['amount_' . $count])) {
            $paypal_args['amount_' . $count] = round($paypal_args['amount_' . $count] / $convert_rate, 2);
            $count++;
        }
        if (isset($paypal_args['tax_cart'])) {
            $paypal_args['tax_cart'] = round($paypal_args['tax_cart'] / $convert_rate, 2);
        }

        if (isset($paypal_args['shipping_1'])) {
            $paypal_args['shipping_1'] = round($paypal_args['shipping_1'] / $convert_rate, 2);
        }
        
        if (isset($paypal_args['currency_code'])) {
			$paypal_args['currency_code'] = 'USD';
	}
    }
    return $paypal_args;
}

function getFromYahoo()
{
    $from = 'USD'; /*change it to your required currencies */
    $to = 'INR';
    $url = 'http://finance.yahoo.com/d/quotes.csv?e=.csv&f=sl1d1t1&s=' . $from . $to . '=X';
    $handle = @fopen($url, 'r');

    if ($handle) {
        $result = fgets($handle, 4096);
        fclose($handle);
    }
    $allData = explode(',', $result); /* Get all the contents to an array */
    return $allData[1];
}

PayPal payment not working for new update of Woocommerce 3.1.2

Updated to work with Woocommerce 3.2.3