6) From economic point of view, what are the main causes of market failure ?

From economic point of view, the main causes of market failure are Incomplete markets, Indivisibilities, Common property resources, Imperfect markets, Asymmetric Information, Externalities, Positive Externalities of Production, Negative externalities of production, Public Goods and Public Bads.
In this present reality, there is non-achievement of Pareto optimality because of various requirements in the working of immaculate rivalry. A vital reason for ecological corruption is business sector disappointment. It implies poor working of business sectors for ecological merchandise and administrations. It reflects disappointment of government arrangement in uprooting business sector twists made by value controls and endowments.
Based on Incomplete markets statement, Markets for certain things are incomplete or missing under perfect competition. The absence of markets for such things as public goods and common property resources is a cause of market failure. There is no way to equate their social and private benefits and costs either in the present or in the future because their markets are incomplete or missing.
Based on Indivisibilities statement, the Paretian optimality is based on the assumption of complete divisibility of products and factors used in consumption and production. In reality, goods and factors are not infinitely divisible. Rather, they are indivisible. The problem of divisibility arises in the production of those goods and services that are used jointly by more than one person. An important example is of road in a locality. It is used by a number of persons in the locality. But the problem is how to share the costs of repairs and maintenance of the road. In fact, very few persons will be interested in its maintenance. Thus marginal social costs and marginal social benefits will diverge from each other and Pareto optimality will not be achieved.
Based on Common property resources, Another cause of market failure is a common property resource. Common ownership when coupled with open access, would also lead to wasteful exploitation in which a user ignores the effects of his action on others. Open access to the commonly owned resources is a crucial ingredient of waste and inefficiency. Its most common example is fish in a lake. Anyone can catch and eat it but no one has an exclusive property right over it. It means that a common property resource is non-excludable (anyone can use it) and non-rivalrous (no one has an exclusive right over it). The lake is a common property for all fishermen. When a fisherman catches more fish, he reduces the catch of other fishermen. But he does count this as a cost, yet it is a cost to society. Because the lake is a common property resource where there is no mechanism to restrict entry and to catch fish. The fisherman who catches more fish imposes a negative externality on other fishermen so that the lake is overexploited. This is called the tragedy of the commons which leads to the elimination of social gains due to the overuse of common property. Thus when property rights are common, indefinite or non-existent, social costs will be more than private costs and there will not be Pareto Optimality.

Based on imperfect markets statement, Pareto efficiency increases under perfect competition. But it declines under market distortions or imperfections. Let us consider a case of monopoly. Initially, monopoly equilibrium is at point E where the private marginal cost curve, PMC, cuts the marginal revenue curve, MR, from below. The monopolist produces OQ1 output at OP1 price. But the production process generates smoke in the air. Therefore, the pollution board levies a tax equal to ТЕ on the monopoly firm. The imposition of a pollution tax is, in fact, a fixed cost to the monopoly firm. Now the social marginal cost curve cuts the marginal revenue curve at point e. The monopolist increases the price of his product from OP1 to OP2 and restricts output to OQ2 and thereby reduces consumers’ surplus to Q2 MLQ1 (= OQ1 LP1 – OQ2 MP2). In fact, Q2 MLQ1 is the social cost of OQ2 output. But the net loss to society is Q2 MLQ1 – TE= eMLT, the shaded area in the figure.

Based on Asymmetric Information statement, Pareto optimality assumes that producers and consumers have perfect information regarding market behaviour. But according to Joseph Stiglitz, “In