India primarily uses a progressive tax system for direct taxes like income tax. In a progressive tax system, the tax rate increases as the income or tax base increases. India's income tax structure has different tax slabs with higher tax rates for higher income brackets. While indirect taxes like GST can be regressive in nature (taking a larger proportion of income from the poor), the overall "tax system" is often characterized by the nature of its direct taxes, making "Progressive taxes" the most appropriate description among the given options for India's major tax structure feature.